The Open Interest Page, From the First Look to a Routine

First 5 Minutes

The question What do I do first, if I read nothing else?

Values in this guide are as of 5 October 2026, read from the source files listed in the Sources section. Anything this guide could not confirm from the product is gathered once, in What we have not verified.

What the Open Interest Page Is

The question What does this page show that the option chain does not?

This guide follows the page from the first click to a routine. A beginner can read each step in order, because every control is named and every figure is worked out. A serious trader can jump to the part needed: the four readings behind the insight verdict, the exact window rules, the max pain arithmetic, the control reference, or the traps. Every picture is a capture of the running page. Where a number or behaviour could not be backed from the product, the guide says so and links to What we have not verified.

Real tool · illustrative dataThe page bar

The whole page, from the page bar down to the strike rail, is pictured in Part A. The name OI appears only on the view switch, where four tabs share one bar. Everywhere else the page spells out Open Interest.

What It Does Not Do

• It places no orders and gives no advice. A bar is a reading of the book.
• It does not say who holds a position. Every open contract has a buyer and a writer, and a hedge, a spread leg and a roll all print alike.
• It does not predict where price goes. The marked levels are references, not promises.
• It does not show other days. It shows the latest trading session; step back within that session with Chart time.
• Strike by strike columns of one expiry, with premium, volume and Greeks, are on the Option Chain. Fast changes across all strikes are on OI Spurts. See Which tool when.

Words to Know Before the First Bar

The question Which few words must I know before any bar makes sense?

Open Interest

The number of option contracts still open at a strike, Calls and Puts counted separately. It counts positions, not trades. A trade that hands an open contract from one holder to another adds to volume and leaves Open Interest as it was.

Strike

The price an option is struck at. The page draws one column per strike, lowest strike on the left. The strike nearest the market price is the at-the-money strike, printed in bold on the rail.

Call and Put

A Call gains when the price rises. A Put gains when the price falls. The page says Call and Put; the code letters CE and PE are the exchange's own abbreviations for the same two, and appear in the product only as codes.

Writer

The seller of an option, who takes the premium and carries the risk. Every open contract has one buyer and one writer, so Open Interest alone never says which side was pushing.

Units, not lots

Open Interest on this page is in units of the underlying, as the data carries it, written in lakh (L) and crore (Cr). It is not divided by the lot size. One lakh is 100000; one crore is 100 lakh. NIFTY's lot is 65 and BANKNIFTY's 30 at 5 October 2026; the exchange revises lot sizes (BANKNIFTY lot not re-checked).

Snapshot

One reading of the whole book for one expiry at one minute. The page keeps the session's snapshots and measures change between two of them.

Window

The stretch of the session a change is measured over: 15m, 30m, 1h, Day or a range you set. The window opens at an earlier snapshot and ends at the newest one.

Wall

A strike where one side's Open Interest is heavy. Within the 15 strikes around the money, the page marks the strike with the most Call Open Interest at or above price (the Call wall) and the one with the most Put Open Interest at or below it (the Put wall), in the insight's key levels.

Build-up

Open Interest and the option's premium read together. Long Buildup: both rose. Short Buildup: Open Interest rose, premium fell. Short Covering: Open Interest fell, premium rose. Long Unwinding: both fell. The chips on the bars are the two-letter codes LB, SB, SC and LU. The names are conventions for how traders read the pattern, not a record of who traded.

Two habits help. Read the strike before the bar: a tall bar at 24100 is a different thing from the same bar at 25000. And read the window before the change: the same strike can add Open Interest over the day and lose it over the last fifteen minutes.

Where the Numbers Come From

The question How fresh is this, and how much can I lean on the time stamp?

Which session the page shows

The page opens on the latest trading session: today during the day, and the last session after the close or on a holiday. This guide found no date control on the page (no date picker found). The only way to look at an earlier moment is Chart time, which steps back within the session. Session minutes run from 9:15 to 3:40 pm.

The history is kept in your browser for speed (up to 600 readings). That cache is the reason the page can open with the morning already drawn. What the insight stamp shows is the time of the newest reading it used, for example 30 Sep 2026, 02:20 pm IST. Quote that stamp, not your clock, when you note what the page showed.

The product's list has 217 F&O underlyings. Open Interest is archived for the underlyings and expiries the collector tracks; whether every one of them has an archive for every expiry is not yet confirmed. A symbol or expiry with nothing archived shows the empty state.

Using It on a Phone

The question Can I run the page from a phone, and what changes?

Yes. Below 768 pixels the page switches to a layout made for a narrow screen. Nothing is removed from the four views; the page draws fewer things at once so that each bar can still be read.

Real tool · illustrative dataThe page on a phone

Real tool · illustrative dataCustomise on a phone

• 10 strikes open on a phone, instead of 21 on a desktop. A phone always draws that many; a count you choose on a larger screen is remembered and used there.
• One wall per side prints its figure, instead of three, and the level marks shorten to Support and Resistance.
• The insight box is a row with a verdict and a chevron. Opening it shows the same reading in a sheet.
• Customise opens from the settings button beside the insight row, because the page bar is not drawn on a phone.
• The view switch and the information button move into Customise. The breadcrumb that carries them is not drawn on a phone, so Customise opens with a View section: Chart shows (the four views) and Chart key and how to read it, which opens the same How to read dialog.
• A strike opens its card on touch. The hit strip of a strike is the full height of the plot but only a few pixels wide at 21 strikes; the strike count is the control that makes it easier to hit. How the touch behaves on a device was not run for this guide (not yet confirmed).

The Screen, From Top to Bottom

The question What am I looking at, part by part?

Real tool · illustrative dataThe page as it opens

1. The page bar. The breadcrumb, an information button, the view switch and Customise. Next section.
2. The insight row. The page's reading in one line: a verdict, the support and resistance it found, the Put/Call Ratio and how that ratio moved. It opens into a box and a detail panel. Part D.
3. The level marks. Four labelled rules across the plot: the last traded price, possible support, possible resistance and max pain. Level marks.
4. The plot. One column per strike, lowest strike on the left. In the Open interest view each column holds a Call bar and a Put bar. Reading the bars.
5. The axis, on the right, with its caption: Open interest, Open Interest change, Put ÷ call · log or Pain · ₹.
6. The strike rail, under the plot. The at-the-money strike is bold in a capsule.
7. The key, which the page keeps in the information button (ⓘ) beside its title. Its Key terms tab says what the colours and textures mean in this view, names the expiry, the day and the window, and gives the lot size. Nothing is printed under the plot unless you have stepped back in time.

Real tool · illustrative dataThe key terms in the information sheet

The Page Bar: Four Views, One Information Button, Customise

The question How do I change what the page draws?

The capsule reads Open interest, OI change, Strike PCR and Max pain. All four read the same board of one expiry; only the drawing changes. The page remembers the view you left on and reopens on it. Press a tab, or move along the capsule with the arrow keys.

When the slot is too narrow for four tabs the capsule becomes a menu showing the current view. It is measured against the room, not against a screen size, so a narrow desktop window gets the menu. On a phone the switch is not in the page bar at all; it sits in Customise, under View.

The small circle beside the title opens a dialog for the view you are on: What it measures, How to read it in numbered steps, and a Caution. Each part has an In the guide link that comes to this page, and Read the full guide at the foot. Escape closes it and returns focus to the button you pressed.

On a phone (768 pixels wide or less) the breadcrumb is not drawn, so the same dialog opens from Chart key and how to read it in Customise, under View.

Real tool · illustrative dataThe information dialog, Open interest view

The button on the right holds everything that used to crowd the chart: the expiry, the window, the chart time, up to four chart switches (fewer in the views that do not use them) and the strike count. Every change applies to the plot at once, so the panel has only Reset and a close cross. It is explained control by control in Part E.

Choosing the Symbol and the Expiry

The question How do I look at another index, a stock or another expiry?

The symbol. Use the search tile in the top bar (Search instruments), or simply start typing a symbol anywhere on the page and the search opens with your letters in it. The address carries the symbol: /open-interest/nifty, /open-interest/banknifty, /open-interest/reliance. Switching the symbol or the expiry clears two things that belong to one book: a rewound chart time and a pinned strike. Your view, window, strike count and switches are kept.

The expiry. In Customise, under Contract, the Expiry control shows the date and the days to expiry, for example 06 Oct with 6 DTE. It opens a list headed Choose expiry, with the weekday, a Monthly tag where it applies and the days to expiry (today on the expiry day itself; a screen reader hears them as “6 days to expiry”). The days are calendar days. Reset in Customise leaves the expiry alone, because it is the contract being read and not a preference.

Real tool · illustrative dataContract

Real tool · illustrative dataThe expiry list

The same page for a stock and for another index

The views are the same for every symbol; what changes is the spacing of strikes, the size of Open Interest and the insight's default window. Below, RELIANCE and BANKNIFTY on the same illustrative day.

Real tool · illustrative dataA stock: RELIANCE

Real tool · illustrative dataAn index: BANKNIFTY

The insight box defaults its Measured over choice to 15 min for an index and Day for a stock, and remembers your choice separately for each kind, so one NIFTY choice does not follow you onto every stock. The chart's own window (Customise › Time) is a different control with its own default, Day; see Part C and Part D.

A symbol or expiry the archive does not hold shows an empty state, not a blank plot.

The Open Interest View: Reading the Bars

The question What does one bar mean, and which bars should I look at first?

Real tool · illustrative dataThe Open interest view

A column is one strike. In it the Call bar stands on the left and the Put bar on the right. A taller bar means more contracts open. The Key terms in the ⓘ button say which colour is which (Calls, Puts); the position inside the column says it too, so the picture does not depend on colour alone.

Calls are heavy above the market price here, and Puts are heavy below it. That is the usual shape, because the strikes people write are mostly out of the money: Calls above price and Puts below it. The ladder is centred on the at-the-money strike; the 21 strikes on a desktop are about ten strikes each side.

The axis on the right counts contracts in lakh and crore, in round steps: 0, 50L, 1Cr, 1.5Cr, 2Cr. The top is the next round step above the tallest bar, so the bars are drawn to the same top the axis prints. The caption reads Open interest.

You cannot print a figure over every bar. The page prints the figure of the three tallest bars on each side (one on a phone), as long as the bar is at least 12% of the plane. If both bars of one strike are among the tallest and are almost the same height, the shorter one gives up its figure so the two numbers do not print on top of each other. A bar shorter than 0.15% of the plane is not drawn at all. Press a strike to read any bar's exact figure.

Real tool · illustrative dataThe tallest Call bar

Real tool · illustrative dataThe strike rail

Real tool · illustrative dataThe axis

The rail prints the strikes under the columns. When the plot is too narrow to label every strike, the rail prints some and skips the rest, always keeping the at-the-money strike. The bars are still all there; only the labels thin out. Choosing fewer strikes in Customise brings the labels back.

1. The bold strike and the LTP line: where price stands.
2. The tallest bar on each side, and how far each is from price. On the illustrative reading the tallest Put bar is 1.78Cr at 24100, 412 points below price, and the tallest Call bar is 1.98Cr at 25000, 488 points above it.
3. The striped tips: how much of each tall bar is new. Next section.

The Striped Tip: What Was Added in the Window

The question How much of a bar is new, and how much was already there?

The top of a bar can carry a striped tip: the contracts added during the window. The Key terms name it: Added: the striped tip of a bar. Its height is the window's increase as a share of the bar, and never more than the bar. A large tip means that strike is still being built; no tip means the position was there already, or Open Interest there fell.

Real tool · illustrative dataOver the whole day

Real tool · illustrative dataThe same bars over 15 minutes

• The standing bar is the same in every window. Only the tip changes, because only the tip is about the window.
• Only additions are striped. A fall in Open Interest does not shorten the bar here; it shows in the OI change view as a bar below the line.
• The tip needs a measured window. Where the window cannot be measured (see the window states) the tips and the key entry are left out.
• It is a switch: Customise › Chart › Move in the window on each bar. Switched off, only the standing bars remain.

Real tool · illustrative dataLevels, tips and tags switched off

The Level Marks: LTP, Support, Resistance and Max Pain

The question What are the four labelled lines, and how are the support and resistance chosen?

Real tool · illustrative dataThe level marks

How the support and resistance are chosen

The page does not just take the tallest bar. It scores every strike within 12 steps of the money on three things, each measured against the largest on its own side: the size of its Open Interest, this session's change in it (the exchange's own change against the previous session) and its traded volume. A band of 3 strikes slides along the ladder, the band with the highest total score wins, and the Open-Interest-weighted centre of that band is snapped to the nearest listed strike. That is why the text in the information dialog says it is a band's centre, not always the single tallest bar.

The weights depend on how close the expiry is, because near expiry fresh writing and volume say more than old positions:

The insight's detail panel prints the weights it used for the day you are on, for example 0.40 × size + 0.35 × change + 0.25 × volume. The weights are the product's own choice (the weights are a product convention), not an exchange rule.

Support and resistance are not the same as the walls

The Call wall is the single strike at or above price with the most Call Open Interest, and the Put wall the single strike at or below price with the most Put Open Interest. Both are read within the 15 strikes around the money (the at-the-money strike and seven listed strikes on each side), the same rule as the Option Chain. They can sit on a different strike from the marked support and resistance, because the marks are a scored band and the walls are one tallest strike. The insight's key-levels table shows both. On the illustrative reading the captures show the Call wall at 25000 and the marked resistance at 24950, and the Put wall at 24100 and the marked support at 24050 (the wall strikes in the captures).

The switch

Customise › Chart › Support, resistance & max pain lines turns the marks on or off. When a badge cannot sit over its own rule without leaving the plot, it moves sideways and a short elbow links it back to its rule, so you can follow badge to rule to axis.

The Build-up Chips: LB, SB, SC and LU

The question What do the two-letter chips over some bars say, and what do they not say?

Real tool · illustrative dataChips over the biggest movers

A chip names how one leg's Open Interest and its premium moved together over the window. Two axes, four patterns:

The rule is the same for a Call and a Put, because it reads the contract's own premium against its own Open Interest. If either axis is exactly flat there is no pattern, and the leg carries no chip. A leg with no matching earlier reading is left out, never counted as zero. The Key terms spell the letters out: LB / SB: Long Buildup and Short Buildup and SC / LU: Short Covering and Long Unwinding. The full name is on the strike card.

Only the five biggest, by default

Forty-two chips over forty-two bars say no more than none do. So the page tags only the five legs with the largest change, counted across both sides together, and every strike still gives its pattern on its card. Customise › Chart has Buildup tags (all or none) and Tags on the biggest movers only. At a strike count that is too dense for every chip, the panel says so: Too many strikes to label every bar at this width. Choose fewer strikes, or rest on a strike to read its buildup.

The OI Change View: Added Above the Line, Closed Below It

The question Where was the book built, and where was it taken down?

Real tool · illustrative dataOI change, over the whole day

The plot draws only the change, not the standing book. A bar above the rule is Open Interest added at that leg in the window; a bar below it is Open Interest closed. Its height is the size of the change, not the Open Interest at the strike. The caption reads Open Interest change and the key says Striped bar: this window's move only.

Real tool · illustrative dataThe signed axis

Real tool · illustrative dataThe key of this view

• One scale across the rule. Both directions use the same step, so a +40L bar is exactly twice a −20L bar. Only the position of the zero rule moves to suit the data: if little rose, the rule sits near the top and the page does not waste half the plot on bars that do not exist.
• The chips are still there over the biggest movers, and the strike card gives each pattern in full.
• It follows the window. Day compares with the first reading of the session; 15m with a reading fifteen minutes earlier. See Part C.
• A window the archive cannot measure draws no bars and says why. Zero would be a lie; the page writes It is not zero.

Real tool · illustrative dataThe last 15 minutes

Real tool · illustrative dataThe last hour

The Strike PCR View: Puts Against Calls, Strike by Strike

The question At which strikes do Puts outweigh Calls, and by how much?

Real tool · illustrative dataStrike PCR

Strike PCR at one strike is the Put Open Interest divided by the Call Open Interest there. A reading of 1.00 means balanced; above 1.00 the strike is Put-heavy, below 1.00 Call-heavy. This is a ratio of two standing counts at one strike. It is not the whole-expiry Put/Call Ratio the insight shows, and it is not the PCR page, which charts a ratio through the session.

Real tool · illustrative dataThe key of this view

Why the axis is a log scale

A ratio is lopsided in both directions: 10 and 0.1 are equally far from balance, but on a plain axis they would sit ten times apart. So the plot draws the log of the ratio. Every rule is ten times the one below it (the key says so): 100, 10.00, 1.00, 0.10, 0.01. The length of a bar is its distance from balance, not the size of the Open Interest. A strike with 2 lakh Puts and 0.2 lakh Calls draws as long as one with 20 crore Puts and 2 crore Calls.

Real tool · illustrative dataThe log axis

• Fitted, not fixed. The plane counts the decades above and below 1.00 that the readings need, and draws every decade the same length. A pinned reading (a strike with no Calls, an infinite ratio; or no Puts, a zero ratio) rides the end rail and the end tick gets a ≥ or ≤.
• Only the extremes print. A bar prints its ratio when it is 10 or more, or 0.1 or less, or infinite or zero (∞ and 0). Printing every bar would turn the plot into noise. Every strike's exact ratio is on its card.
• The window does not move it. Each ratio is the standing book at that strike. The key says so: Each ratio is the standing book at that strike, so the window does not move it.

Real tool · illustrative dataA strike card in this view

The Max Pain View: What the Expiry Would Cost the Writers

The question Where does the expiry cost option writers least, and how is that worked out?

Real tool · illustrative dataMax pain

Max pain is the strike at which, if the expiry settled exactly there, the Call writers and Put writers together would pay out the least. The idea is a sum, not a prediction. For each possible settlement strike K:

The first sum is what the Call writers would pay: every Call struck below K is in the money by (K − strike). The second is what the Put writers would pay: every Put struck above K is in the money by (strike − K). The plot stacks the two so you can see which side carries the cost at each strike, and traces their total across the top; the floor of that line is max pain.

A worked sum (illustrative, three strikes)

Read the table by column. Settling at 24400, the 24500 Puts and 24600 Puts are in the money: (100 × 20L) + (200 × 10L) = 4000 lakh-points. Settling at 24500, the 24400 Calls pay (100 × 10L) = 1000 and the 24600 Puts pay (100 × 10L) = 1000, 2000 in all. Settling at 24600 costs 4000 again. The smallest is 24500, so max pain is 24500. In rupees, 2000 lakh-points means 2000 × 1 lakh units = ₹2000 lakh, or ₹20 crore.

Real tool · illustrative dataThe axis

What the page does with it

• The whole chain. The sum runs over every listed strike of the expiry, not over the strikes drawn. Choosing 11 strikes does not change max pain.
• In rupees. Open Interest in the archive is in units, so points × units is rupees. The page does not multiply by the lot size; that would count it twice. The axis reads Pain · ₹ in lakh and crore.
• Ties go to the strike nearer the at-the-money strike. If the chain holds no Open Interest at all, or every strike costs the same, the page falls back to the at-the-money strike and the plot says No open interest stands anywhere in this chain, so settlement would cost neither side anything.
• The window does not move it. The key says Full book; Window does not move max pain. It moves only when the book moves.
• The marker. The amber dot sits on the floor of the line; the amber rule and badge are the same level on the Max pain flag, if the level marks are on.

Real tool · illustrative dataThe key of this view

Real tool · illustrative dataThe position read under the plot

The page also says in words where spot sits against the level: Spot is above Max Pain or Spot is below Max Pain, with the distance in points, in per cent and in strikes away. It is printed only when the chain names one real max pain strike (not on a tie, an empty chain or the at-the-money fallback). It is a position, not a verdict: there is no Bullish or Bearish word, and the note says A level read from the book, not a prediction. The same read is in the card of the max pain strike and in the Max Pain pill of the Option Chain.

Real tool · illustrative dataA strike card in this view

Real tool · illustrative dataThe card of the max pain strike

The Strike Card: Every Figure Behind a Bar

The question How do I read the exact figures of one strike?

A bar has a rough height and nothing else. The strike card is where its figures are. It opens three ways, and shows the same reading in each:

• Rest the pointer on a strike for about half a second. The delay is deliberate: dragging across 21 strikes would otherwise open 21 cards.
• Move to it with the keyboard. Arriving on a strike opens its card at once, because choosing it is the intent.
• Press or tap it (or press Enter or Space on it) to keep the card open. A pinned card has a cross, Close strike detail, and an extra line for the distance from spot.

Real tool · illustrative dataThe card as a hover, Open interest view

Real tool · illustrative dataThe same card, pinned

What is on a card, view by view

The head also carries up to two tags for what the strike is: Possible support, Possible resistance, Max pain, At the money. The strike's distance from spot reads like 112 pts / 0.46% below spot.

Real tool · illustrative dataOI change view, 24600

When a figure is missing, the card says why

A leg that was not in the book at the window's start is not shown as a zero change. The card prints the standing Open Interest and one clause naming the cause: Only one snapshot has been collected., No snapshot reaches back that far yet., No snapshot close enough to the window's open. or Not listed at the window's open. A strike with no contracts says No contracts listed at this strike. A change that rounds to nothing prints with no percent and a flat dash rather than a signed zero.

The figures on the card reconcile: the change is the difference of the two printed figures, on one scale chosen for the pair, so 26.25L → 26.09L and −0.16L always agree on screen.

The Window: Which Stretch of the Session Is Measured

The question What does 15m, 30m, 1h or Day compare, and when is it not available?

Real tool · illustrative dataCustomise, Time

The window is the stretch over which a bar's change is measured. It opens at an earlier snapshot and ends at the newest one; the change is the newest reading minus the opening reading, leg by leg. Choose it in Customise › Time › Window. The page opens on Day, and remembers your last choice.

A 5-minute window exists in the page's model and drives the insight's 5 min choice, but the chart's Window capsule does not offer it; the capsule begins at 15m.

Which views use the window

Open interest (for its striped tips) and OI change use it. Strike PCR and Max pain do not: a ratio of standing books and a payout of the standing book have no window. Their chart keys say so, and in a terminal widget pinned to one of them the Window control is not offered at all.

A window the page cannot measure says so

In Customise, a window longer than the session so far is greyed out, so you cannot pick what cannot be measured: 15m needs at least 15 minutes since 9:15, 30m needs 30, 1h needs 60, and Custom needs 15.

Two windows on one page

The chart has its own window (Customise › Time, default Day). The insight box has a separate Measured over choice (5 min, 15 min, Day; Part D). They answer different questions and use slightly different tolerances (the chart's 2.5 minutes; the insight's 90 seconds for 5 min and 150 seconds for 15 min). The insight's Day also measures against the previous session's close when it can read that, while the chart's Day measures against the session's own first reading. A verdict over 15 minutes beside a chart over the Day is normal; read each against its own label.

A Custom Window: Choose Both Ends

The question How do I measure just the stretch between two clock times?

Real tool · illustrative dataCustomise, Time, Custom chosen

• Custom pins both ends. The right edge is the newest snapshot at or before To, not the newest in the archive; the standing bars, the support and resistance and the max pain are read at that edge too. A Custom window ending at 13:20 does not read its wall off the 15:30 close.
• The left edge is the newest snapshot at or before From, on the same date. An opening reading from another day is never used, even if it shares the clock time.
• The clocks move in steps of 5 minutes, From at least 15 minutes before To, and To no later than the newest reading. Raising From past To pushes To along with it.
• The same 2.5 minutes tolerance applies at both ends. If the archive has a hole at either edge, the window says it is not measured.
• A remembered Custom does not reopen as Custom. A fixed slice of the clock reopened before the session reaches it would read nothing, so the page opens on Day and keeps your From and To for next time.

Chart Time: Step Back to an Earlier Reading

The question How do I see the book as it stood earlier in the session?

Real tool · illustrative dataCustomise, Chart time, stepped back

Chart time is the page's replay. The arrows step the chart back and forward by 5 minutes; the slider runs from 9:15 to the newest reading; Back to latest returns. Everything the page draws and says is then read as of that moment: the bars, the level marks, the strike cards and the insight box, with the window measured back from there.

• The newest reading keeps its own minute. If the newest snapshot is 2:19, the stepper says 2:19 and Latest, not 2:15. The five-minute grid applies to the steps: one step back from 2:19 lands on 2:15, so the 2:15 to 2:19 book is not skipped.
• It is never remembered. Reopening the page tomorrow on yesterday's 11:05 would chart a stale instant with no sign it was not live. Changing the symbol or the expiry also returns to the latest.
• It is only within the session shown. Chart time cannot go to an earlier day (no date picker found).

Real tool · illustrative dataThe page while rewound

Real tool · illustrative dataThe line under the plot while rewound

A rewound page cannot pass for the live one: a line under the plot says Chart shows 12:40 in plain text, and the button beside it reads Back to latest (its accessible name says Chart shows 12:40. Back to the latest reading).

The First Half Hour: Why a Window Can Say It Is Not Ready

The question What can I use at 09:28, when the session is only minutes old?

A change over 15, 30 or 60 minutes compares the newest reading with a stored one that many minutes earlier. At the start of the session no such reading exists. The captures below are the real page at 09:28 on the illustrative day, with the 15m window remembered from an earlier visit.

Real tool · illustrative dataOI change over 15m at 09:28

Real tool · illustrative dataCustomise, Time at 09:28

Real tool · illustrative dataThe insight row at 09:28

• The standing figures do not wait. The bars of the Open interest view, Strike PCR and Max pain are the book as it is, so they are drawn from the first reading. Only change needs history.
• Use Day early. Day compares with the first reading of the session (or, in the insight, the previous close), so it is the first window that can speak. Greyed windows come back as the session ages.
• A late first reading makes a partial day. If the archive starts at 9:40, the Day hint reads Partial day · since 9:40 and the page will not call it the whole day.
• The insight box decides for itself whether it can measure each reading, with its own tolerances (90 seconds and 150 seconds). What it prints in the first quarter-hour was captured above for one reading only; open the box and read its Comparison window line rather than assuming (first-quarter-hour insight not watched live).
• Early readings are noisy. Morning Open Interest includes rolls and the previous day's hedges being put on. A small base moves a lot in percent. Prefer a bar's size to its percentage.

The Insight Row: One Line That Summarises the Page

The question What is in the row above the plot?

Real tool · illustrative dataThe insight row, closed

For a stock the row reads the same, with Day (Today) marked instead of 15m:

Real tool · illustrative dataThe row for RELIANCE

How the Verdict Is Reached: Four Readings, Counted

The question What exactly is behind "Mixed indications", and can I check it?

Real tool · illustrative dataThe insight, opened

The verdict is a rule of thumb, printed beside its working. It is not trained or backtested, and the product says so. It counts four readings, each tagged bullish, bearish or neutral by a rule shown next to it, and each measured or not:

The count. A side needs a lead of 2 or more readings over the other. Fewer than 3 measured readings name no direction at all. A reading that could not be measured is shown as Not measured and never as a neutral vote. Here: two bullish, one bearish, one neutral. The lead is 1, which is less than 2, so the verdict is Mixed indications, and the box says no side leads by two.

Real tool · illustrative dataThe Measured over capsule

Measured over

• 5 min and 15 min use the reading that far back in this session, within 90 seconds and 150 seconds. A seven-minute gap is not "5 min".
• Day uses the previous session's close when the page can read it: each leg's exchange previous-day Open Interest, with premiums, levels and the index from the closing reading. When it cannot, it counts from the session's first reading and every surface says since 9:15 am.
• The default is 15 min for an index and Day for a stock, remembered per kind and per browser.

Because the chart's window and the insight's are different controls, a Day chart can sit under a 15-minute verdict. The row and the box always name their own window.

The Detail Panel: Every Figure With Its Working

The question Where do I check the arithmetic behind a line of the insight?

The button Full detail and calculations opens a panel from the right, headed NIFTY Open Interest detail with the expiry and the window under it. Across the top are shortcuts to its six sections: How the verdict is decided, Positions in the window, The Put/Call Ratio, Key levels, 5 min, 15 min and Today and Data and scope. Each figure can be expanded to its formula, the same formula with this reading's numbers, the rule it was tested against, and what it covers (Show the 7 calculations).

Real tool · illustrative dataThe top of the panel

• Legs matched (122 of 122 (100%)): the share of current legs that have an opening figure. A leg without one is left out of every total and chip, never counted as zero.
• What is uncertain lists, in plain words, what the reading cannot say: that Open Interest does not say who opened it, how much of the change has no build-up label (910 of the 30.06L that moved has no build-up label, because those legs' prices did not move), that the ratio here counts all 61 strikes while the PCR page counts a band around the money, that support and resistance score only the strikes near the money and that Open Interest is not divided by the lot size.

Real tool · illustrative dataPositions in the window, and the four-window board

The four-window board re-measures the three largest changes over the chart's own windows. The longest column is the baseline, and a cell that differs from it is marked with a dotted edge. It answers is the short-term pattern the same as the day's? A cell reading not measured means the archive did not reach back far enough, which is different from a pattern that was measured and flat.

Real tool · illustrative dataKey levels

In the ladder, Today is the change against the exchange's previous-day figure, and From NIFTY is the distance in points and per cent. A row that is a wall and also the marked level is merged (Also the call wall). On the illustrative reading: Call wall 25000 (1.98Cr, +35.28L today, 488 points above), marked resistance 24950 (1.54Cr, +32.14L, 438 above), max pain 24550 (37.65 above), Put wall 24100 (1.78Cr, +6.94L, 412 below), marked support 24050 (1.52Cr, +13.45L, 462 below) (the wall strikes in the captures). A level in the table can be pressed to jump to its strike on the chart.

Real tool · illustrative dataThe Put/Call Ratio

Real tool · illustrative dataData and scope

The 5 min, 15 min and Today section shows how each PCR movement was measured: the two readings, their clocks and the gap between them. The Data and scope section says where each input came from, which strikes and which stretch of time each figure covers, and the time of the newest reading. The page is not a stream: it re-reads its archive about once a minute, so read the stamp.

The panel closes with its cross or Escape. The panel's own words on its method end with: Missing inputs are named as unavailable, never shown as zero.

Customise, Control by Control

The question What does every switch in Customise do?

Real tool · illustrative dataThe Customise panel

The panel is a dialog: focus moves into it, Tab stays inside, Escape closes it and focus returns to the Customise button. It does not lock the page's scroll, so the plot behind it stays readable. On a desktop the view switch and the information button are in the page bar, not here (on a phone they are here, under View), and the page remembers the view you left on.

Real tool · illustrative dataChart

Real tool · illustrative dataStrikes

How Many Strikes: 10, 11, 15, 21, 31 or 41

The question How many strikes should I draw, and what do I give up as the ladder widens?

The ladder is centred on the at-the-money strike and clamped at the ends of the book, so asking for 21 near the edge of the list still draws 21. The page opens on 21 on a desktop and 10 at 768 pixels or less, until you choose a count. A stop is dimmed once a smaller stop already shows every strike the expiry lists, because the larger ones would draw the same ladder.

Real tool · illustrative data11 strikes

Real tool · illustrative data41 strikes

The count changes only the picture. The insight box still reads all the strikes of the expiry, the Max pain view still sums over all of them, and the support and resistance search still reaches 12 steps from the money. The opened insight says so: All 61 strikes read · 21 drawn on the chart. The strike count is the one control that trades how many strikes you can see for how well you can read them.

Keyboard and Touch

The question Can I use the page without a mouse, and what does a touch do?

Every strike column is a button with a name that reads its figures aloud: Strike 24500. Call open interest 1234500; put open interest 1500000. Activate for strike details. The PCR view reads the ratio and the Max pain view reads the payouts in rupees. Figures read aloud carry no digit grouping, so they match what is printed. The columns are only a few pixels wide at 21 strikes, so a pointer or finger has to be accurate; the full-height strip and the strike count are what make it workable. Whether a screen reader reads the page well end to end was not run for this guide (not yet confirmed).

A Worked Reading, Start to End

The question What does a careful reading of one page look like, step by step?

Everything below is read from the illustrative NIFTY page of 30 September at 14:20, six days before the 6 October expiry. The numbers are made up for this guide, so the reading is an exercise in method, not a view on any market.

Real tool · illustrative dataThe page being read

1. Scope. The foot says 6 Oct expiry · On 30 Sep, the whole day and the stamp says 02:20 pm IST. So this is the 6 October book, measured from this morning, as it stood at that time.
2. Price. LTP 24512.35; the bold strike is 24500. The market stands almost on a strike.
3. The shape. Puts are heavy below price: 1.78Cr at 24100 and 1.52Cr at 24050. Calls are heavy above it: 1.98Cr at 25000, 1.90Cr at 24900, 1.54Cr at 24950. The book is wide: roughly 400 points of heavy Puts below, 400 of heavy Calls above.
4. The levels. The marked support is 24050 and the marked resistance 24950; the walls in the captures are 24100 and 25000 (the wall strikes in the captures). Max pain is 24550, 37.65 points above price. All of these are references.
5. What is new. The striped tips are longest on the Call bars at 24900 to 25000. The key-levels table says the 25000 Call is +35.28L today. More Calls were added at the top of the range through the day.
6. The patterns. LB chips over the Calls at 24900, 24950 and 25000: Open Interest and premium rose together there. SC chips over the Calls at 24650 and 24700: Calls were closed while their premium rose. Calls added far above, Calls closed nearer the money, on a day when the index rose: a statement about what happened to two numbers.
7. The balance. Strike PCR is above 1 below price and under 1 above it, the usual shape. The whole-expiry ratio is 0.84, 84 Puts for every 100 Calls, against 0.86 at the previous close: the Call side grew a little relative to the Put side.
8. The insight. Two readings lean bullish (positions 100% bullish; NIFTY +0.14% over the 15 minutes), one leans bearish (PCR 0.84 is under 0.97), one is neutral (levels unchanged). A lead of one is short of two: Mixed indications. Legs matched 122 of 122, so no leg was left out.

The Traps

The question What misreadings does this page invite, and how do I avoid them?

1. Reading Open Interest as direction

Every open contract has a buyer and a writer. A tall Call bar is not bullish or bearish by itself, and the page says so. Use it as a map of where positions stand, then read price.

2. Treating a wall as a ceiling or a floor

A wall is where many contracts stand. Price can stop short, stall, pass through or ignore it. A wall that was heavy at the open can be a different strike by the afternoon.

3. Reading the striped tip as the whole bar

The tip is only what was added in the window. The rest of the bar was already there. A big bar with a tiny tip is an old position; a big tip on a small bar is a new one, but small.

4. Believing a percentage on a small base

+2900% from 2 thousand to 60 thousand contracts is a rise of 58 thousand. The strike card prints the percent beside the lakh figure so you can see the base. Read the size before the percentage.

5. Believing a far strike's PCR

Far from the money one side is nearly empty, so the ratio is huge or tiny. The bar length is distance from balance, not size. Check the two Open Interest figures on the card.

6. Taking max pain as a target

It is a sum over the standing book. It moves with every change in Open Interest, and price can settle elsewhere. The page says: Max pain is not a price target or guarantee.

7. Comparing two windows without noticing

A Day chart under a 15-minute verdict, or a 15m card read beside a Day card, answers different questions. Every figure sits under a label that names its window; read the label.

8. Reading a short window as established

A very short window reacts to one large order, rolls or a hedge being placed. Check the nearby strikes and a longer window before treating a move as established, as the page's own caution says.

9. Reading a partial day as a whole day

If the first reading was late, the Day hint says Partial day · since 11:05. A change measured since then misses what came before. The hint is there to be read.

10. Reading the wrong expiry

The bars belong to one expiry, named in the Reading entry of the Key terms (the ⓘ button). A weekly and a monthly book look alike and are not the same. After switching, check the Reading and the stamp.

11. Treating the verdict as a signal

It is a count of four coarse readings with a lead of two needed. It has not been trained or backtested. Use it to decide where to look in the detail panel.

12. Ignoring hedges, spreads and rolls

A spread leg, a hedge and a roll to the next expiry all change Open Interest and premium the same way an outright position does. Open Interest cannot tell them apart.

13. Reading expiry-day falls as conviction

On the expiring contract, Open Interest falls through the last day as positions are closed or settle. A large fall in the OI change view on expiry day may be this, not conviction; compare it with earlier expiry days rather than a normal day (general market behaviour, not a figure the page checks).

Risk Notes

The question What does this page leave out that a trader has to carry?

• It is analysis, not advice. The page places no orders and gives no recommendation. The verdict words describe a tally of readings.
• It cannot see who is at risk. The writers of the heavy bars carry the risk; a position that is a hedge elsewhere is not a position at risk. Open Interest does not say which.
• Selling options carries large risk. A level near a heavy bar does not limit a writer's loss. Margin, charges, taxes and the cost of getting in and out are not computed here. The Strategy Builder works the payoff of a position before anything is placed.
• The data is coarse. It is a snapshot about once a minute, and a thin strike can sit untraded for a long stretch.
• Levels are not stops. Putting a stop or a target at a marked level because the page marked it is relying on a reference as if it were a rule.
• Lot sizes, strike spacing and expiry weekdays change. The ones in this guide are as of 5 October 2026 and were not re-checked with the exchange (lot sizes and expiry days not re-checked).

Two Routines: Expiry Day and Positional

The question What do I do, in order, on expiry morning and on an ordinary day?

The expiry-day routine

1. Reading. Open the ⓘ Key terms and confirm the expiry is today's (the expiry list says today) and read the stamp.
2. The weights change. At 0 or 1 day to expiry the support and resistance weigh size 0.20, change 0.40 and volume 0.40, so they follow fresh writing and traded volume more than old positions. The marks can move more than on a normal day; the insight's Key levels table says by how much.
3. OI change, 15m. Set the window to 15m. Look at the strikes within a few hundred points of the money: where is the book being added, and where closed? Press the biggest bars for the card.
4. Max pain against price. The Max pain view and the insight's Price against max pain row give the gap. It is a reference; it moves with Open Interest, and Open Interest falls on the expiring contract as the day goes on.
5. Strike PCR near the money only. Far-strike extremes often come from thin books, so start with the five or six strikes either side.
6. Rewind once. Use Chart time to look at the 9:30 and 11:30 books and see which walls moved and which held.
7. Write down the reading with its stamp, so that you can compare it with the next one.

The positional routine

1. Pick the expiry you hold. Customise › Contract. Read the Reading in the Key terms.
2. Day window, Open interest view. Find the standing walls and the support and resistance. At five or more days to expiry the weights favour standing positions (0.60 size).
3. Day change. In OI change over the Day, which strikes grew and which shrank since the open? In the insight, set Measured over to Day to compare with the previous close.
4. Compare two expiries. Switch the expiry and see whether the walls sit on the same strikes.
5. Check the ratio. The whole-expiry PCR and its movement against the previous close, with the knowledge that it is a standing ratio with its own thresholds (0.97 and 1.03).
6. After the close. The page keeps showing the last session, so you can read the closing book in the evening.

Which Tool When

The question Which page answers my question best?

The chain's own Open Interest columns (the standing figure, the change, the change in percent and the build-up label) are explained cell by cell in the Option Chain guide. This page draws the same standing and change figures as bars.

Controls and Labels, Quick Reference

The question What is every control on the page called, and where does it live?

What Each Message Means

The question The page shows a sentence where the bars should be. What is it telling me?

The loading, empty and error states were not captured as pictures for this guide; the sentences are quoted from the page's source.

Glossary

The question What does this word mean on this page?

Open Interest

Contracts still open at a strike. A count of positions, not trades. Written OI only on the view switch.

Strike

The price an option is struck at; one column on the plot.

Call, Put

The two kinds of option. CE and PE are the exchange's codes for them.

Writer

The seller of an option, who takes the premium and carries the risk.

Unit, lakh, crore

Open Interest here is in units of the underlying. 1 lakh = 100000; 1 crore = 100 lakh. Not divided by the lot.

Snapshot

One reading of the whole book of one expiry at one minute.

Window

The stretch of the session a change is measured over; opens at an earlier snapshot, ends at the newest.

Wall

The strike with the most Open Interest on one side of price, read within the 15 strikes around the money: the Call wall at or above price, the Put wall at or below it.

Build-up

Open Interest and premium read together: Long Buildup (LB), Short Buildup (SB), Short Covering (SC), Long Unwinding (LU).

At the money (ATM)

The strike nearest the market price; bold on the rail.

LTP

Last traded price of the underlying in the newest snapshot.

Possible support, possible resistance

The centre of the strongest scored band of Put (support) or Call (resistance) Open Interest within 12 steps of the money. References.

Max pain

The strike where the expiry would cost its writers the least in total, summed over the whole chain.

PCR, Strike PCR

Put Open Interest divided by Call Open Interest: over the whole expiry (insight) or at one strike (the Strike PCR view).

DTE

Days to expiry, counted as calendar days.

Striped tip

The part of a bar that was added during the window.

As of

The instant the chart is drawn for when Chart time is stepped back.

Questions People Ask

The question What do readers ask most?

What We Have Not Verified

The question Which statements in this guide could not be checked against the product?

• The collector's schedule. The model's comment says about one reading a minute; the collector runs outside this repository and was not inspected, so gaps and the exact timing are not confirmed.
• No date picker. The page opens on the latest trading session and this guide found no control to choose another day. Not confirmed on every build.
• Which underlyings and expiries have an archive. The product lists 217 underlyings; whether each has an archive for each expiry is not confirmed.
• Lot sizes, strike spacing, expiry weekdays and holidays (the BANKNIFTY lot of 30, the Tuesday dates in the pictures; the NIFTY lot of 65 is confirmed). Exchange facts that change; not re-checked with the exchange.
• The weights of the support and resistance score. They are the product's choice, not an exchange rule; no study of them is in the source.
• The verdict's usefulness. The product states it is not trained or backtested. This guide makes no claim about how often it is right.
• What the insight shows in the first quarter-hour of a live session, and when each window becomes ready by the clock. Captured for one reading only.
• The brief marker on a leg that moved between two readings (a leg that shifts by at least half a percent of the tallest bar). Read from the source, not watched in motion.
• Touch and screen-reader behaviour on a real phone and with assistive software. Read from the source, not run on a device.
• What the insight's Live updates / Saved reading label promises. Read from the source as whether the box follows the newest reading; no streaming is implied and none was observed.
• The wall strikes in the captures. The pictures show the Call wall at 25000 and the Put wall at 24100, ten and eight strikes from the at-the-money 24500. The walls are now read within the 15 strikes around the money (24150 to 24850 on that reading), so these captures predate that rule and the figures may differ after a re-shoot.
• The terminal (Cockpit) widgets that pin one view of this page are not covered or pictured here.
• Expiry-day behaviour of Open Interest on the expiring contract is general market behaviour, not something the page checks.

Sources

The question Where in the product does each statement come from?

Values in this guide are as of 5 October 2026. Every number the product can change is listed with its source file in scripts/guides/open-interest-parts/limits.mjs. The pictures are regenerated by scripts/guides/shot-open-interest.cjs from the mock market in scripts/guides/open-interest-mock.cjs.