The Straddle Workspace: Premium, Expected Move and Five Views

A

Part A of 6 The number What a straddle premium is, which strike counts as at the money, the expected move at 0.85 times it, the breakevens, and where the figures come from. 5 topics

The question each topic answers

1. What do I do in my first five minutes, and what can I leave for later?
2. What is a straddle premium, and why is it the first number worth reading on this page?
3. Which strike does the page call at the money, and why can it differ from the strike nearest the price?
4. How far is the market priced to move, and where does a bought straddle break even?
5. Where do the numbers come from, how old can they be, and what is polled rather than streamed?

Your First Five Minutes

What do I do in my first five minutes, and what can I leave for later?

The Straddle workspace tells you what the at-the-money straddle costs, how big a move that price implies, and whether it is getting dearer or cheaper. It places no order and makes no forecast. If you read nothing else, read these six steps.

1. See the priceThe straddle premium is a Call plus a Put (what it is).
2. See the move0.85 times it, and the breakevens (the three numbers).
3. See the changeSteady, rising or falling, by a visible rule (the verdict).
4. See the causePrice, volatility or time (why it falls).
5. See the legsPremium Decay, Multi-Strike, Multi-Straddle (the views).
6. See the limitsWhat the page does not know (limits).

What a Straddle Premium Is

What is a straddle premium, and why is it the first number worth reading on this page?

Every option chain lists, for each strike, a Call and a Put, each with a last traded price. Take one strike, add its Call price to its Put price, and you have that strike’s straddle premium. The at-the-money straddle is the one at the strike closest to the money. It is the cheapest straddle that still reacts to a move in either direction, and it is the one this page tracks through the session. Which strike counts as closest to the money is not as obvious as it sounds; the next part settles it.

The premium is a price per unit, in index points. NIFTY’s lot is 65 units, so one lot of this straddle costs about ₹18125 to buy (278.85 × 65), before costs. The page prints the per-unit figure everywhere; the per-lot figure is a multiplication you do yourself.

Real tool · illustrative dataThe number on the pageSwipe sideways to see all of itEnlarge

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What It Is Not

• Not a direction. A Call and a Put are held together, so a high premium means a big move is priced, up or down. It carries no view of which.
• Not a profit or a loss. It is what the pair costs now. Whether a straddle makes money depends on the price you paid and where the market ends, which this page does not know.
• Not a forecast. It is the options market’s price today. It moves as the market moves, as time passes and as implied volatility changes (why a premium falls on a day the index rose).
• Not an order. The page places no trade and recommends none. It reads prices.

A Strangle in One Paragraph

If the Call and the Put sit at different strikes, the pair is a strangle. It is cheaper than a straddle, because both options are further from the money, and it needs a bigger move to pay. The page lets you build one from the Legs bars in Customise and prices it the same way: the Call price at one strike plus the Put price at the other. When it does, its heading says Strangle instead of ATM Straddle (how to lock a strike and build a strangle).

Which Strike Counts as At the Money

Which strike does the page call at the money, and why can it differ from the strike nearest the price?

A straddle is only “at the money” at one strike, and the page has to choose it at every reading. The tempting answer is the strike nearest the price. That is not what the page uses.

The Rule

The page uses the forward-anchored at-the-money strike: the strike nearest the forward, the price the underlying is expected to reach on the expiry date once interest is added. The app takes the at-the-money strike that its chain data gives, when the data gives one, and otherwise works out the forward from the Call and Put prices. Only the Option Chain’s highlighted ATM row is chosen by the nearest strike to the price.

Because the forward sits a little above spot, the two rules usually agree and sometimes differ by one strike. They differ when the price sits just below the middle of the gap between two strikes: the forward is a little above the price and can lie past the middle.

Here is what the choice costs, on the same four strikes. The two candidate straddles are close in price, which is why the choice matters less than it looks, and why the page names the strike every time it quotes a premium.

The page says so on screen. When the two strikes differ, the insight box adds a caveat that names both strikes: the at-the-money strike is 24550, the strike nearest NIFTY (24512.35) is 24500, and the premium, breakevens and expected move are priced at 24550, as on the Option Chain.

Real tool · illustrative dataHow the verdict is decided, with the caveatsSwipe sideways to see all of itEnlarge

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The Strike Step

As the price moves, the forward crosses the middle between two strikes and the at-the-money strike steps to the next one. Straddles at the two strikes are different contracts with different prices. A jump in the line at that moment is a change of contract, not a change of the market. On the frozen day the at-the-money strike changed 14 times between the open and 2:20 pm. The insight box counts these, lists each one in a table, and refuses to call a premium “rising” or “falling” on a step alone (the rule is in the insight part).

Expected Move, Range and Breakevens

How far is the market priced to move, and where does a bought straddle break even?

The page turns the premium into three levels. They answer different questions and are easy to confuse, so each one has its own rule.

Expected Move: 0.85 × the Straddle

The expected move is 0.85 times the straddle premium, not the whole premium. It is shown as a distance either side of the price: ±237 on the frozen day, where the full premium is 278.85. The same rule is used by the Exp Move pill on the Option Chain and by the chain’s insight card, so the three places always agree. The page calls it a pricing convention: not a probability, not a forecast. It is not a standard deviation either, and it carries no chance of the index finishing inside it. The reason for the 0.85 is a convention of the product, and this guide does not claim a hit rate for it (what we have not verified).

Read it as a distance, not as a promise. “The options market is pricing about ±237 points from here” is a statement about today’s prices. The index can end the expiry far outside it or never leave it.

Move Range: Centred on the Price

The range is the price plus and minus the expected move, so it follows the price, not the strike. On the frozen day it is 24275 to 24749. It is the same for a locked strike or a strangle, because the question it answers is how far the price may travel from where it stands now.

Breakevens: the Full Premium Either Side

A straddle that is bought and held to expiry breaks even where the Call or the Put has earned back the whole premium: the Call strike plus the premium, and the Put strike minus the premium. On the frozen day that is 24271 and 24829. These levels are exact for expiry and ignore brokerage and taxes. For a strangle each leg uses its own strike. The breakeven band is always wider than the expected move band, which is the whole point of showing both: a buyer needs more than the expected move to profit.

Real tool · illustrative dataThe detail panel, Expected move and breakevensSwipe sideways to see all of itEnlarge

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Points and Rupees

For an index the expected move is in index points; for a stock it is in rupees. The page words it that way where it speaks (“Expected move plus or minus 237 points” against “rupees” for a stock) and prints stock levels to one or two decimals where a whole number would hide a small move. Other symbols shows a stock.

Where the Numbers Come From and How Fresh They Are

Where do the numbers come from, how old can they be, and what is polled rather than streamed?

The Straddle workspace reads a minute archive of saved option chains, not the live chain that the Option Chain page polls. That one fact explains most of what you see on screen: why a chart can end a few minutes before the clock, why a Custom window cannot reach the future, and why a price on this page can differ slightly from the same strike on the chain.

Polled, Not Streamed

Nothing here arrives as a continuous stream. The chain is fetched again about every 5 seconds in market hours; the minute archive is read again about every minute. Read the time stamp in the insight row to see how old a reading is.

Last Traded Price, Not a Quote

The premium is the last traded price of each leg in a saved snapshot. It is not a bid or an offer, and a contract that trades rarely can show an old price. A leg with no traded price is never counted as zero: the reading is left out, because half a straddle printed as a whole one would be wrong. The insight box says it plainly: “Premiums are last traded prices in saved snapshots; they may not be tradable now.”

Implied Volatility Is Solved, Not Copied

The ATM IV line is worked out again from the traded prices, at the forward, with a fixed 6.5% yearly interest rate. The collector’s own stored IV figure is zero on most day files, so reading it would draw nothing. Where the stored figure exists, the two agree within a few hundredths of a point.

The Clock the Page Trusts

Times on the page are the snapshot’s own time, in Indian Standard Time, never the clock of your device. A windowed change, such as 15 minutes, is measured between two snapshots, and a baseline that is more than 90 seconds off its target for 5 minutes (150 seconds for 15) is reported as not measured rather than quietly widened. The session runs from 09:15; the Custom window can reach 15:40, the close the app assumes from 3 August 2026 (it was 15:30 before; exchange timings are not verified here).

Real tool · illustrative dataThe detail panel, Data and scopeSwipe sideways to see all of itEnlarge

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B

Part B of 6 The page The screen, the insight row and the rule behind its verdict, the full calculations, and the phone layout. 4 topics

The question each topic answers

1. What is on the screen, and which part do I read first?
2. What do the verdict, the chips and the three changes say, and how is the verdict decided?
3. Where can I see every figure worked out, with its formula and the real numbers?
4. How do I use the page, and this guide, on a phone?

The Screen at a Glance

What is on the screen, and which part do I read first?

The Straddle workspace is one page with a bar on top, a one-row insight card and a chart. The chart runs to the foot of the window, on a desktop and on a phone; on a phone a one-line scope note sits under it. There is no table of numbers to scroll: the page is built to be read from the top down in about ten seconds. Open it from the sidebar (Straddle, in the Volatility and Risk group beside GEX Levels and IV) or at /straddle. The underlying and the expiry follow what you chose elsewhere in the app, and the expiry can also be changed in Customise.

Real tool · illustrative dataThe workspace on NIFTYSwipe sideways to see all of itEnlarge

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• Page barThe title Straddle with an information button, the five views, and Customise.
• Insight rowA verdict, two chips (Move and Straddle), three changes (5m, 15m, Today), the legs and the days to expiry, and a View insight button.
• Chart headingThe premium at the latest reading or the one under the pointer, its change since the window opened, and the context Latest · Expected move ±X.
• Tools rowPlain-text interval tabs (1m 5m 15m 30m 1h), the line chips on the Overview (Straddle, Spot, Max pain, Call leg, Put leg), the crosshair and full screen. There are no indicators, chart types or chart settings.
• The plotThe lines that are on, against the clock, with a one-line readout at the top left and a small zoom pill at the bottom centre.
• Scope lineOn a phone: one line saying which expiry, part of the session and time step the lines are of. On a desktop it is not shown (the chips name the lines and the choices sit in Customise); the foot appears only to say as of with a way back while the chart is rewound, and to name the strike when it is not the at-the-money one.

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The Five Views

The view you leave on is remembered in this browser. The window (Day, 1h and so on) is shared by all five views: if you read the last hour on the Overview and turn to Multi-Strike, you are still reading the last hour. The 1 Month span belongs to the Overview alone, because the other views are built on picks that belong to one expiry, and a month spans several; leaving the Overview on 1 Month puts you back on Day.

Real tool · illustrative dataThe information dialogSwipe sideways to see all of itEnlarge

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The Insight Row and Box

What do the verdict, the chips and the three changes say, and how is the verdict decided?

The row above the chart is the page’s own reading of the premium. It is a short, rule-based summary, not a forecast. It reads the minute archive directly, so changing the chart’s time step or window changes what is drawn but never what this row says. It follows the chart in one way only: while you have rewound the Overview to an earlier reading, it reads as of that reading.

Real tool · illustrative dataThe insight row, closedSwipe sideways to see all of itEnlarge

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The Row, Cell by Cell

How the Verdict Is Decided

The rule is short and visible. Take the change in the premium over the window you chose (5 min, 15 min or Day). If it is more than 1% of the starting premium upward the verdict is Premium rising; more than 1% downward, Premium falling; otherwise Premium steady. A change of one 0.05 tick or less is always steady, because on a small premium one tick is wider than one percent. The page takes the percentage at its printed step of 0.1%, so a change that prints +1.0% is steady and +1.1% is rising. The colour of each cell in the row follows the same band, so the verdict and its cell never disagree. The rule has not been trained or back-tested; it is arithmetic on one change.

Measured Over: 5 min, 15 min, Day

Inside the open box a three-way control sets the window the verdict reads. The default is 15 min for an index and Day for a stock, and your choice is remembered for each. 5 min and 15 min compare with the snapshot that far back in the same session, and only if that snapshot is within 90 seconds (5 min) or 150 seconds (15 min) of its target; otherwise the window reads not measured and the control shows it greyed with the reason in the detail panel. Day compares with the previous session’s close when the page holds it, and otherwise with the first reading of the session, and then says so (“Since 9:15”). A close from a different expiry is no baseline.

Real tool · illustrative dataThe insight, openSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataMeasured over 5 minSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataMeasured over DaySwipe sideways to see all of itEnlarge

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A Strike Step Is Not a Move

The premium follows the at-the-money strike, and that strike steps when the price crosses the middle of two strikes. On the frozen day it stepped from 24450 at the previous close to 24550 now. The straddle at 24550 is a different contract from the one at 24450, so part of the change may be only the step. When a change is bigger than the band, the page asks one more question before it names a direction: did the earlier strike’s own contract, priced now, move the same way, beyond the band? On the Day window the line is down 6.55 (−2.3%), more than the band. But the 24450 straddle itself changed by +2.65 (+0.9%), the opposite sign, so no direction is called and the window reads steady in grey (the picture above). On the 15 min window the strike also stepped, but the change of −0.60 is inside the band, so it is steady on that ground alone. Without this check a wide-step stock could print a large rise or fall on a step alone.

The Four Sentences and the Caveats

• The premium gives the premium then and now, the change over the span and whether it is inside the steady band.
• The breakevens sentence gives the two breakevens and the pricing range, 0.85 × the straddle around the underlying.
• The volatility sentence gives ATM IV now and then, and the underlying’s change over the same span.
• Max pain is the fourth sentence, in the page’s own words: the strike where the total payout to option buyers at expiry is smallest.
• The caveat at the right is chosen by the situation: a clock note (near expiry, falls are normal), whether the strike follows the money or is locked, the forward-against-nearest note, the 0.85 note, and the last-traded-price note.

Full Detail and Calculations

Where can I see every figure worked out, with its formula and the real numbers?

The button Full detail and calculations in the open insight opens a panel from the right with seven sections. It is the page’s open book: every figure is shown with its formula, its working in the real numbers and the scope it covers. Use the section tabs at the top to jump. Each section can show its picture of the numbers, then a fold named Show the N calculations.

Real tool · illustrative dataThe detail panel, topSwipe sideways to see all of itEnlarge

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• How the verdict is decidedSix steps: legs, premium now, baseline, change, strike step, result, each passing, failing or neutral, then What is uncertain.
• The premiumThe straddle and its two legs, the session open, the session range, how many times the at-the-money strike changed, and the same contract priced at the open and at the previous close.
• Expected move and breakevensThe four levels of the previous part, each worked.
• Volatility and decayATM IV, its change, the underlying’s change and, for the intraday windows, the time alone.
• LevelsBreakeven up, move range high, max pain, the underlying, move range low, breakeven down, from highest to lowest with each one’s distance from the underlying.
• 5 min, 15 min and TodayHow each of the three changes is measured, with both readings.
• Data and scopeData time, expiry, legs, how many minute snapshots were read and the previous close used.

Real tool · illustrative dataHow the verdict is decidedSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataThe calculations openedSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataThe premiumSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataEvery strike change of the sessionSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataVolatility and decaySwipe sideways to see all of itEnlarge

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Real tool · illustrative dataLevelsSwipe sideways to see all of itEnlarge

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Real tool · illustrative data5 min, 15 min and TodaySwipe sideways to see all of itEnlarge

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Time alone is a model estimate: the baseline premium times the square root of (time left now divided by time left then), with price and volatility held where they were. It is shown for the intraday windows only, because it counts calendar time and a night or a weekend would overstate the decay. Across a weekend the calendar clock also lowers the volatility solved at the earlier end; the panel says so beside the ATM IV change on a Day window.

Using It on a Phone

How do I use the page, and this guide, on a phone?

At 768 pixels wide or less the page changes to its phone layout, and the charts use a compact form from 1200 pixels. The five views move into a menu in the page bar that names the view you are on, such as Overview ▾. The Customise button leaves the page bar, and the settings button in the top bar opens the same panel. The insight opens as a sheet over the page with a close button, instead of pushing the chart down.

The Chart on a Phone

• One-line head. The chart heading fits on one line: the name, the premium and its change.
• One row of tools. The interval tabs, then a Lines n button, where n is how many lines are on. It opens a small menu of the same toggles as the chips on a desktop: Straddle, Spot, Max pain, Call leg and Put leg. A tap outside the menu, or Escape, closes it.
• Fewer controls. No crosshair switch, no full screen and no zoom pill.
• Right axis only. The premium keeps its axis on the right. Spot, max pain and the breakevens are still drawn to their own scale but without an axis of their own, so the plot keeps its width; read their values in the readout.
• The chart fills the screen. On the Overview, Multi-Strike and Multi-Straddle the chart takes the height left under the insight row. Premium Decay and Price vs Open Interest stack several charts and keep their own heights.
• One-line scope note under the Overview chart, cut short with an ellipsis rather than wrapped.

Real tool · illustrative dataThe page on a phoneEnlarge

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Real tool · illustrative dataThe insight on a phoneEnlarge

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Real tool · illustrative dataCustomise on a phoneEnlarge

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• Back to latest sits under the chart when it is rewound.
• The pickers in Customise scroll inside their own box: scroll the table, then the panel.
• This guide has the same layout on a phone: a wide picture scrolls sideways inside its frame, and the Enlarge button opens it full size.

C

Part C of 6 The Overview The premium line and its chips, the readout, the window and time step, rewinding, locking a strike or building a strangle, and the 1 Month span. 5 topics

The question each topic answers

1. What does each line on the Overview mean, and how do I read it?
2. How do I choose which part of the session I see, and how fine the line is?
3. How do I look at the page as it stood earlier in the session?
4. How do I price a strike other than the one at the money, or a strangle?
5. What does a month of premium look like, and why does the line break?

The Overview Chart

What does each line on the Overview mean, and how do I read it?

The Overview draws the straddle premium through the session as one thin line in the accent colour, with its latest value tagged on the right axis and a dotted guide running across to the tag. By default that line is alone. Chips above the plot add four more lines, and Customise holds three further readings. The right axis is the premium; on a desktop a left axis appears for the price of the underlying when a line on that scale is on.

Real tool · illustrative dataThe Overview chartSwipe sideways to see all of itEnlarge

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The Heading

Real tool · illustrative dataThe chart headingSwipe sideways to see all of itEnlarge

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The heading names what is plotted (ATM Straddle, or Straddle for a locked strike, or Strangle), prints its value at the reading under the pointer or the latest one, and then its change since the first reading of the window, in points and percent. With one reading only it prints no change, because a measured standstill would be a false statement. The context at the right reads Latest · Expected move ±X, or the time of the reading under the pointer in place of Latest. On 1 Month the change is against the previous close, and it is withheld across an expiry roll or a gap; the context then names the date and the expiry of the close.

The Tools Row

Under the heading one compact row holds everything the chart offers. It is the same on all five views, except that only the Overview has chips.

• 1m 5m 15m 30m 1hinterval tabsPlain text tabs for the time step, the same setting as Time step in Customise. Not shown on 1 Month.
• ChipsOverviewStraddle, Spot, Max pain, Call leg and Put leg. Each turns its line on or off (see below).
• Crosshairtarget iconShows or hides the crosshair. On by default. Not shown on a phone.
• Full screenarrows iconThe page itself goes full screen, with the view tabs and Customise above the chart, so the five views can be changed without leaving it. Not shown on a phone.

There are no indicators, no chart types and no chart settings on any Straddle chart: the page is for reading the premium, not drawing on it.

The Chips and the Lines

The chips and the Chart switches in Customise are one setting: press a chip and the matching switch in Customise turns with it, and the other way round. Your choice is remembered in this browser. A chip that is on is filled and its dot is solid; a chip that is off is faint.

Three more readings stay in Customise only, because they are second readings rather than lines you flip while looking:

The Max pain line switch draws max pain only. The chart has no expected-move line: the expected move is in the chart heading, the Move chip in the insight row and the Exp Move pill on the Option Chain. If every line is off, the plot says No chart lines selected and points you to the chips.

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The Readout

A single line at the top left of the plot prints the time, then the value of each line that is on: for example 01 Oct, 14:20  Straddle 278.85  Spot 24512.35 with Spot on. With the pointer over the chart it reads that moment; otherwise it reads the latest reading. The premium always leads. ATM IV, Time-decay only and Breakeven (as a range, low to high) appear in it only while they are on in Customise. It replaces the floating hover box, which covered the lines it described, and the key that used to sit under the chart: the chips now name the lines.

Real tool · illustrative dataThe pointer on the chartSwipe sideways to see all of itEnlarge

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Of the fall from 303.10 to 278.85 (−24.25), time alone accounts for about −6.16. The rest is the lower implied volatility (12.92% at the open, 12.1% now), the price’s own move and the change of strike. The chart heading prints −24.10 (−8.0%) because it measures from its first drawn reading, the 5 minute bucket ending 09:19 at 302.95; the detail panel’s session open is 303.10. The next part takes this apart.

The Scope Line

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The scope line says what the lines are of: the expiry, which part of which session, and the spacing between readings. A phone keeps it as one line under the chart, cut short rather than wrapped. A desktop leaves it out: the chart takes the whole height of the window and the choices are read in Customise. What stays under the chart on a desktop is the way back while the chart is rewound (as of and a Back to latest button), and the strike when it is not the at-the-money one (Strike 24500 (ATM 24550)).

Zoom and Keyboard

• Zoom pilldesktopA small pill at the bottom centre of the plot: zoom out, zoom in, pan to earlier and later readings, and reset. It shows while the pointer is over the plot. A phone has none.
• KeyboardThe chart responds to the arrow keys to move through time, plus and minus to zoom, and 0 to fit.

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Choosing the Part of the Session and the Time Step

How do I choose which part of the session I see, and how fine the line is?

Two choices in Customise decide what the lines are made of: the window, which part of the session, and the time step, how many minutes between readings. Both apply to all five views.

• Window15m, 30m, 1h, Day or CustomDay is the whole session since 09:15 and the default. 15m, 30m and 1h end at the reading the chart ends on. An option is greyed when the session so far is shorter than it: at 9:40 a one-hour window would only be the same 25 minutes as Day.
• Custom From and To5 minute stepsTwo choices, never less than 15 minutes apart. To can reach the minute of the newest reading. A remembered Custom is not restored on the next visit; the page opens on Day and keeps your From and To for next time.
• Time step1m, 5m, 15m, 30m or 1hAlso the interval tabs on the chart. Default 5m. The page keeps the last reading in each step, counted from 09:15. A step of 1m draws every minute; 1h draws about six readings.

Real tool · illustrative dataThe 1h windowSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataA Custom windowSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataTime step 1mSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataTime step 30mSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataCustomise with the Custom windowEnlarge

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The first reading of a step is the last reading of its first bucket, so with a 5m step the line starts at the 09:19 reading, not 09:15. The change in the heading is measured from that first drawn reading. The insight row does not use these buckets: it reads every minute (The Insight Row and Box).

Rewinding with Chart Time

How do I look at the page as it stood earlier in the session?

The Chart time control in the Time section steps the Overview back through its readings. The chart then ends at that reading, and the insight row reads as of it. Use it to ask what the page said when the move began, without waiting for a replay. It exists on the Overview only, and not on 1 Month. It is a moment, not a preference, so it is never remembered.

Real tool · illustrative dataChart time stepped backEnlarge

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Real tool · illustrative dataThe chart rewoundSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataThe insight followsSwipe sideways to see all of itEnlarge

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Changing the time step, the window, the expiry or the symbol puts the chart back on the latest reading. Hold the rewound view to compare what the strike, the premium and the verdict were at the turn with what they are now.

Locking a Strike and Building a Strangle

How do I price a strike other than the one at the money, or a strangle?

By default the Overview follows the money: at every reading it prices the at-the-money strike, so the line changes contract whenever the strike steps. Two choices hold the strikes still, which turns the line into the price of one position.

• Strike (Contract section)a drop-downATM · 24550 follows the money. Any listed strike locks both legs at it. The hint reads Follows the ATM as it moves, Both legs at one strike or Call and Put at different strikes. On 1 Month the choice is greyed: 1 Month follows the ATM at each session close.
• Legs barsLegs sectionA bar chart of Call Open Interest and Put Open Interest by strike, 21 strikes around the ATM (11 on a phone). Click a Call bar to set the Call strike and a Put bar to set the Put strike. Two different strikes make a strangle.

Real tool · illustrative dataCustomise on the OverviewEnlarge

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Real tool · illustrative dataThe Legs barsEnlarge

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The page changes its words to match. A locked strike reads Straddle and the line under the chart names the strike with the ATM beside it: Strike 24500 (ATM 24550). Two strikes read Strangle and the line under the chart names both strikes. The insight keeps your strikes too and says so: “The strikes are held where you locked them, so this is one position’s premium; it is no longer the at-the-money price of movement.”

Real tool · illustrative dataLocked to 24500Swipe sideways to see all of itEnlarge

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Real tool · illustrative dataA strangleSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataThe Expiry choiceSwipe sideways to see all of itEnlarge

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A lock or a strangle belongs to one expiry. If you change the expiry or the symbol, the page returns to following the money. If a locked strike is not in the chain it cannot be priced, and the page also falls back to the money rather than show an empty chart.

The 1 Month Span

What does a month of premium look like, and why does the line break?

Choose 1 Month under Span in Customise and the Overview draws one point for each session close on a date axis, about 21 sessions. There is no clock on this axis, no time step and no window. Each point is the at-the-money straddle at that day’s close, on that day’s nearest expiry, and the newest point is the latest reading of the current session.

Real tool · illustrative dataCustomise with 1 MonthEnlarge

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Real tool · illustrative dataThe Overview on 1 MonthSwipe sideways to see all of itEnlarge

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Why the Change Is Withheld at an Expiry

The collector seals each close on the nearest expiry, which changes every expiry. The straddle at one close and the next can therefore be different contracts. The page marks the first close on a new expiry (the chart heading says new expiry when you point at it) and prints no change figure from the close before it, because that change would be a change of contract and not a move of the market. The premium line is broken there, so the two sides read as two contracts; the spot line, the same instrument across the roll, stays joined. Where a session has no close file the page leaves a gap and does not fill it in. The note under the chart counts all three. The PCR page treats 1 Month differently and draws one expiry only (PCR guide).

Real tool · illustrative dataThe note under the chartSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataA close under the pointerSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataWhile the closes are readSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataWith no past closesSwipe sideways to see all of itEnlarge

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D

Part D of 6 The other four views Premium Decay, why a premium falls on a day the index rose, Price vs Open Interest, Multi-Strike and Multi-Straddle. 5 topics

The question each topic answers

1. How is each leg I pick gaining or losing value through the session?
2. Why can the premium fall on a day the index rose?
3. For one strike, how do its prices and its Open Interest move together?
4. What is the price of several legs together?
5. How do the straddles of several strikes compare?

Premium Decay

How is each leg I pick gaining or losing value through the session?

The Overview adds the Call and the Put together. Premium Decay pulls them apart: it draws each leg you pick on its own, in two stacked charts that share the clock. Use it to see which side of a straddle carried a move, and how fast a far-out leg dies.

Real tool · illustrative dataPremium Decay as it opensSwipe sideways to see all of itEnlarge

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The Two Charts

Each chart has the same minimal tools row as the Overview (interval tabs, crosshair and full screen; no chips) and the same one-line readout at the top left of the plot, which prints the time and each leg’s value. Under both charts a line for the underlying runs on its own scale for context, named by the chip NIFTY spot · left axis (on a phone, NIFTY spot: the phone draws it without an axis). The legend lists each leg as a chip you can press to hide or show it. The legend stays on a desktop, because it is the only place that says which colour is which leg; the scope line under the charts is a phone-only line (the expiry, window and time step are in Customise). A hidden leg keeps its place in the colour order, so hiding one does not recolour the others, and hidden legs reset when you change expiry or symbol.

Real tool · illustrative dataThe Premium Decay chartSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataThe raw premium chartSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataA leg hiddenSwipe sideways to see all of itEnlarge

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The Baseline

• Day OpendefaultChange since the window opened: each leg’s price minus that leg’s own first reading in the window. The lines fan out from zero. Read it for the whole-session shape of decay.
• 1m CloseChange from the reading before: each reading minus the one before it. The first reading has nothing before it and is dropped, not shown as a false zero. The lines swing around zero. Read it for how jumpy each leg is. The name says one minute; with a larger time step it is the previous drawn reading.

Real tool · illustrative dataThe 1m Close baselineSwipe sideways to see all of itEnlarge

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Picking Legs

The legs are picked in Customise (the leg picker). Premium Decay offers two quick adds: Around the ATM and Around a strike, each adding both legs of every strike within ±1, ±2, ±3, ±5, ±7 or ±10 of the centre. There is no cap on the number of legs here. A leg missing from a reading is a gap in its line, never a flat value.

Real tool · illustrative dataSeven strikes pickedSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataPremium Decay, no legs pickedSwipe sideways to see all of itEnlarge

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Why a Premium Can Fall on a Day the Index Rose

Why can the premium fall on a day the index rose?

On the frozen day NIFTY stood at 24450.46 at the first reading and stood at 24512.35 at 2:20 pm, up 61.89 points. The at-the-money straddle fell from 303.10 to 278.85. A straddle gains from a move in either direction, so a rise in the index does not lift it by itself. Three things move a straddle’s premium.

The price rose, but only by 62 points, small against a premium of 303.10: a straddle needs a move of about its own price to pay. Meanwhile time passed, and volatility eased. That is why the premium fell on a day the index rose. This is not a fault of the page; it is how a straddle behaves.

The Overview lets you see this: turn on the Spot chip, and ATM implied volatility and Time-decay only in Customise, and watch the premium follow neither the Spot line nor the dashed time line alone. The Call leg and Put leg chips, or Premium Decay, show which side paid.

Price vs Open Interest

For one strike, how do its prices and its Open Interest move together?

This view takes one strike (the live ATM unless you pick another in Customise) and draws four panels for it from the same readings. It is the place to ask whether the price of a strike’s options moved with, or against, the positions built at it.

Real tool · illustrative dataPrice vs Open Interest for 24550Swipe sideways to see all of itEnlarge

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The strike Put Call Ratio is the Put Open Interest divided by the Call Open Interest at that strike only, not across the chain. It is left out where the Call Open Interest is zero or a leg is missing. If the archive has no baseline to measure the change from, the last panel says: “Open Interest change is not carried for this strike in this window.” Each panel can go full screen.

Real tool · illustrative dataPrice vs Open Interest, Price panelSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataPrice vs Open Interest, Straddle premium panelSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataPrice vs Open Interest, Open Interest panelSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataPrice vs Open Interest, Open Interest change panelSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataCustomise on this viewEnlarge

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Multi-Strike

What is the price of several legs together?

Multi-Strike draws the legs you pick on one chart, up to 20. A Call and a Put at the money, or a Call far above and a Put far below, or a basket of several. The Lines choice in Customise decides whether you see them one by one or added. The chart has the minimal tools row (interval tabs, crosshair, full screen) and the one-line readout, which prints each leg’s value with a dot in its colour, then spot. The key under the chart names each line and lets you hide or show it; it stays on a desktop because it is the only place that says which colour is which leg. The scope line beside it is phone-only.

Real tool · illustrative dataMulti-Strike, IndividualSwipe sideways to see all of itEnlarge

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• IndividualdefaultOne line for each picked leg. Several legs on one side are drawn in paler shades by pick order.
• Call vs PutThe picked Calls added together as one line, and the picked Puts added together as another.
• CombinedEvery picked leg added into one line: the premium of the whole basket per unit.

Sums obey one rule: a reading counts only if every leg being added has a real price at that reading. A missing leg is never treated as zero, which would understate the cost. This holds for a single leg too: where the archive has no price for a leg at some time (it may store 0.00 there), that leg’s line breaks into a gap, and the neighbouring readings are not joined by a straight stroke, as that would show a price that was never quoted.

Real tool · illustrative dataMulti-Strike, Call vs PutSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataMulti-Strike, CombinedSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataCustomise on Multi-StrikeEnlarge

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Real tool · illustrative dataAt the limit of 20Enlarge

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Real tool · illustrative dataMulti-Strike, no legs pickedSwipe sideways to see all of itEnlarge

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The page prices the sum per unit. A basket of one Call and one Put at one strike is a straddle; use Multi-Straddle for several strikes that way. A sum of legs is a price, not a position: it does not know which legs you would buy or sell.

Multi-Straddle

How do the straddles of several strikes compare?

Multi-Straddle picks whole strikes, up to 10, and plots each strike’s straddle (its Call price plus its Put price). Use it to see how the premium falls off as you move away from the money, or to compare the strike you hold with its neighbours. The chart has the same minimal tools row and one-line readout as Multi-Strike. The key under the chart names each strike’s colour and hides or shows its line; it stays on a desktop for that reason, and the scope line goes (the choices are in Customise).

Real tool · illustrative dataMulti-Straddle, IndividualSwipe sideways to see all of itEnlarge

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• IndividualdefaultOne line for each picked strike, in ten colours that repeat if you pick more.
• CombinedThe straddles of all picked strikes added into one line, at readings where every picked strike has a price.

Real tool · illustrative dataMulti-Straddle, CombinedSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataCustomise on Multi-StraddleEnlarge

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Real tool · illustrative dataAt the limit of 10Enlarge

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This view picks a strike whole, so it cannot make a strangle or take one leg: use Multi-Strike for that. A strike missing from a reading leaves a gap in its line.

E

Part E of 6 Customise and the picker Every control and its default, the strike leg picker, other symbols and the same number on the Option Chain. 4 topics

The question each topic answers

1. What can I change, what are the defaults, and what does the page remember?
2. How do I pick legs and strikes, and what happens at the limit?
3. What changes for BANKNIFTY or a stock?
4. Where else does the same premium and expected move appear?

Customise, Control by Control

What can I change, what are the defaults, and what does the page remember?

Every choice lives in one panel: the Customise button in the page bar (the settings button in the top bar on a phone). It has the same sections in the same order for all five views, and each view adds only what it reads. Every change applies at once, so there is no Apply button: only Reset and Close. The panel is a dialog: focus moves in, Tab stays inside, Escape closes it and focus returns to the button.

Which Sections Each View Shows

Contract

• Expiryevery viewThe shared expiry list with the days to expiry of each. A chain with no saved readings for the expiry shows the page’s empty state.
• StrikeOverviewATM · 24550 (default), any listed strike, or the strangle you built. Disabled on 1 Month.
• StrikePrice vs Open InterestEvery listed strike, the ATM marked. It opens on the live ATM; a pick the chain does not list is ignored.

Time

• SpanOverviewOne session (default) or 1 Month.
• Windowall views15m, 30m, 1h, Day or Custom; Day is the default.
• From and ToCustom window5 minute steps, at least 15 minutes apart.
• Time stepnot on 1 Month1m, 5m, 15m, 30m or 1h; default 5m. The interval tabs on each chart set the same value.
• Chart timeOverviewEarlier and later reading, a slider and Back to latest.

Chart

• Eight switchesOverviewPremium on; Call leg premium, Put leg premium, Spot, ATM implied volatility, Time-decay only, Max pain line and Straddle breakeven off. Time-decay only is not offered on 1 Month. Five of them are also the chips on the chart (Straddle, Call leg, Put leg, Spot, Max pain): a chip and its switch are one setting, so pressing either changes both (the chips).
• BaselinePremium DecayDay Open (default) or 1m Close.
• LinesMulti-StrikeIndividual (default), Call vs Put or Combined.
• LinesMulti-StraddleIndividual (default) or Combined.

Reset, and What Is Remembered

Reset puts the page back as it opens: the lenses at their defaults, the reading live over the whole day. It leaves the expiry and your picks alone, because they are the contract being read, not a preference.

The Strike Leg Picker

How do I pick legs and strikes, and what happens at the limit?

Premium Decay, Multi-Strike and Multi-Straddle share one picker in Customise. It has two parts: a row of pills, one for each pick, and a table of strikes to add from.

Real tool · illustrative dataThe pickerEnlarge

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• PillsOne for each pick, tinted by side. The × removes it. Empty, it says No legs selected yet. (or No strikes selected yet.).
• The tablelegs modeOne row for each strike of the latest reading. Add Call becomes Call × once picked, so a press toggles. The Call and the Put of a strike are separate picks.
• The tablestrikes mode (Multi-Straddle)Two columns, Strike and Action: Add or Remove ×. A strike is picked whole.
• Opens on the moneyThe table is centred on the ATM row when it opens and when the expiry changes. Picking or removing never moves your scroll position.
• The limit20 legs, 10 strikesAt the limit the Add buttons you have not used are disabled, not hidden, and a line says N is the most this chart plots. Remove one to add another. Premium Decay has no limit.
• Quick addsPremium DecayAround the ATM and Around a strike: choose ±1, ±2, ±3, ±5, ±7 or ±10 and press Add. Both legs of every strike within that range are added, with no duplicates.
• Starting picksEach list opens on the live ATM once for each symbol and expiry: Premium Decay and Multi-Strike on both ATM legs, Multi-Straddle on the ATM strike. Clear them all and the page keeps the empty chart. A new expiry starts over on its own ATM.

Real tool · illustrative dataCustomise on Premium DecayEnlarge

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A strike is matched exactly. If a strike is not in an early reading, for instance on a stock whose ladder grew during the day, that reading gives no point for the leg. The page never substitutes the nearest strike, because a series that changed strike without saying so would look like a market move.

Other Symbols

What changes for BANKNIFTY or a stock?

Nothing in the page is NIFTY-only. Change the underlying in the app and the same five views read it. What changes is the unit, the strike step and the expiry rhythm. The pictures here use an invented BANKNIFTY and an invented RELIANCE.

Real tool · illustrative dataBANKNIFTYSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataBANKNIFTY insightSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataRELIANCESwipe sideways to see all of itEnlarge

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Real tool · illustrative dataRELIANCE insightSwipe sideways to see all of itEnlarge

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The page reads the symbols the app lists. Which ones have a minute archive of saved readings is the collector’s business: if one has none, the page shows its empty or First reading state.

The Same Number on the Option Chain

Where else does the same premium and expected move appear?

You do not need this page to read the premium. In the Option Chain’s Advanced view the line that carries the spot price also carries two pills built from the same row: ATM Straddle with its IV on the left, and Exp Move with its range on the right. (Customise on the chain switches each pill on or off; the Simple view hides them.)

Real tool · illustrative dataThe Advanced chain’s market lineSwipe sideways to see all of itEnlarge

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The pills’ range is the strike plus and minus the full premium: 24271 to 24829, the breakevens, not the move range. The figure after the ± is 0.85 × the straddle. So the Exp Move pill prints both ideas at once; read the number as the move and the bracket as the breakevens.

Real tool · illustrative dataThe chain’s insight boxSwipe sideways to see all of itEnlarge

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The chain’s one standard deviation range is larger than the expected move because it is built from implied volatility, not from the straddle. They are different measures. Use the chain for the premium of a given strike by eye, and this workspace to watch it through time.

F

Part F of 6 Using it Which tool when, routines for expiry day and the week, worked examples, traps, the empty states and the limits. 6 topics

The question each topic answers

1. Which page do I open for which question?
2. How do I use it through an expiry day, and over a weekly cycle?
3. What do the figures look like worked end to end?
4. What do readers get wrong, and what is the risk in one place?
5. What do the empty and unsure states mean?
6. What does the page not do?

Which Tool When

Which page do I open for which question?

Routines for Expiry Day and for the Week

How do I use it through an expiry day, and over a weekly cycle?

On an Ordinary Day

• Before the open: look at the previous close’s premium (the Today figure compares with it).
• After 9:20: read the first reading and the verdict. With one reading the page says First reading.
• Through the day: check the three changes and the strike in the insight row. Ask whether a change is only a strike step.
• Late: switch on Time-decay only in Customise and compare, to see how much of the fall was the clock.

On Expiry Day

• The gist reads expires today and the insight says falls are normal this close to expiry.
• The premium is small and the tick band governs: one 0.05 tick or less is steady, whatever the percentage.
• The at-the-money strike steps often as the price crosses strikes. Read the strike table in the detail panel before you trust a jump.

Over the Week

• On 1 Month, compare closes the same number of days before each expiry, never close to close across a roll.
• Use Multi-Straddle to see how the premium of the strikes around the money differs, and Chart time to revisit the turn of a move.

Worked Examples

What do the figures look like worked end to end?

Every number is from the invented market of the pictures (1 October 2026, 2:20 pm). None is a quote.

Example 1: Move or Breakeven?

The market is priced for about ±237 points; a buyer needs the index beyond 24829 or below 24271 at expiry, before costs. That is wider than the move, so a buyer needs more than the priced move.

Example 2: A Fall That Is Only a Strike Step

The line is down by 6.55, more than the 1% band, while the contract that was at the money at the previous close is up by 2.65. The contracts disagree, so the page does not call a fall: the Day verdict reads steady and says the strike step accounts for it.

Example 3: The Day

From 09:15 to 2:20 pm the premium moved 303.10 → 278.85, low 278.00, high 304.05, with 14 strike changes. Against the previous close (285.40 at 24450) the change is −6.55 (−2.3%), a change larger than the 1% band, yet the Day verdict reads steady because the earlier strike’s own contract rose (Example 2). The underlying is up 80.55 on the day.

Example 4: What a Strangle Saves

The 24700 Call and the 24300 Put together cost less than the straddle (the strangle chip prints its own premium in the picture above) because both legs are out of the money. The breakevens are the Call strike plus the premium and the Put strike minus it: further apart than a straddle’s.

Traps and Risks in One Place

What do readers get wrong, and what is the risk in one place?

• Reading the premium as a direction. It prices size of move, not side.
• Calling the full straddle the expected move. The move is 0.85 × the straddle; the full premium is the half-width of the breakevens.
• Treating the chain’s ATM row as the priced strike. The page prices the forward-anchored strike.
• Reading a strike step as a market move. Check the strike in the insight row and the table of strike changes.
• Trusting a last traded price as a quote. A rare contract can show an old price.
• Joining a month across an expiry. The page breaks the line for a reason.
• Treating any figure as advice. Nothing here recommends a trade.

When the Page Is Empty or Unsure

What do the empty and unsure states mean?

Real tool · illustrative dataData unavailableSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataFirst readingSwipe sideways to see all of itEnlarge

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What the Page Does Not Do

What does the page not do?

• It places no order and gives no advice.
• It does not forecast. The expected move is a convention and the verdict is arithmetic.
• It does not know your position, costs, margin or taxes.
• It does not stream: the chain is fetched about every 5 seconds and the minute archive about every 60 seconds.
• It keeps about a session and a half of minute readings in the browser; a month is only session closes.
• It prices last traded prices, not bids and offers.
• It does not model costs in breakevens.

What We Have Not Verified

Glossary

What does each word mean?

Straddle

A Call and a Put at the same strike and expiry, bought or sold together. Its price, the straddle premium, is the Call price plus the Put price.

Strangle

A Call and a Put at different strikes. On this page two different strikes chosen in the Legs bars make a strangle.

Call and Put

A Call gains when the price rises above its strike; a Put gains when the price falls below its strike.

Premium

The price of an option. The straddle premium is the price of the two options together. It is a price, not a profit.

Last traded price (LTP)

The price of the most recent trade in a contract. It can be old for a contract that trades rarely, and it is not a quote you can necessarily trade at now.

At the money (ATM)

The strike taken as closest to the price. On this page it is the strike nearest the forward, which can sit one strike away from the one nearest the price.

Forward

The price implied for the underlying on the expiry date: the spot price carried forward by interest. It is a little above spot and the gap grows with the days left.

Strike

The fixed price an option is written on. The option chain lists many strikes in steps (50 for NIFTY in the pictures).

Expected move

On this page, 0.85 times the straddle premium, read as a distance in index points or rupees either side of the price. A pricing convention, not a forecast.

Breakeven

The expiry price at which a position neither gains nor loses. For a bought straddle: the Call strike plus the premium, and the Put strike minus the premium, before costs.

Max pain

The strike at which the total payout to option buyers at expiry is smallest. A level read from the book (computed from Open Interest), not a prediction.

Implied volatility (IV)

The yearly percentage move that the option prices imply. A higher IV means dearer options. The page solves it from the traded prices at the forward.

Time decay (theta)

The part of an option price that wears away as expiry nears, all else equal. It speeds up in the last days.

Vega

How much an option price changes when implied volatility changes by one point.

Open Interest

The number of contracts still open at a strike. It is published with a delay, so it can trail the price.

Put Call Ratio (PCR)

Put Open Interest divided by Call Open Interest. In Price vs Open Interest it is worked out for one strike only.

Lot

The number of units in one contract. Premium is quoted per unit; multiply by the lot size for the rupees of one lot.

Expiry and days to expiry (DTE)

The date an option ends. The page shows calendar days left (DTE), counted from today.

Reading and snapshot

One saved copy of the option chain at a moment. The collector saves about one a minute; the page draws one reading for each time step from them.

Minute archive

The day files of saved snapshots the page reads, merged with the snapshots this browser has saved itself.

Baseline

The earlier reading a change is measured from: five minutes back, fifteen minutes back, or the previous close, depending on the window.

Steady band

A change of one percent of the starting premium, or one 0.05 tick, or less. Inside it the verdict reads steady.

Strike step

When the at-the-money strike moves to the next strike as the price crosses the middle of two strikes. The new straddle is a different contract, so a jump in the line is not a market move.

Expiry roll

On 1 Month, the first close on a different expiry from the one before. The first close on the new expiry is a different contract, so the premium line is broken there and no change is printed from the close before.

One standard deviation (1 SD)

The move that implied volatility prices in by expiry: price × IV × the square root of the time left. The Implied Volatility page uses it; it is not the expected move of this page.

Readout

The one line at the top left of each Straddle chart that prints the time and the value of each line drawn, at the pointer or at the latest reading.

Chips

The small toggles above the Overview chart (Straddle, Spot, Max pain, Call leg, Put leg) that turn lines on and off. They share one setting with the Chart switches in Customise; on a phone they sit in the Lines menu.

Polled

Asked for again at a set interval. The page does not receive a continuous stream: the chain is fetched again about every 5 seconds, the minute archive about every minute.

Questions

What do readers ask most?

Sources

Every statement rests on the app’s source or is marked as not verified. Constants are listed with the file that holds them.