Open Interest vs Volume: What the Volume Bars on Your Chart Show and What Open Interest Adds
Volume counts the contracts traded in a period, the bars under your candles. Open interest counts the contracts still open at the end of the day, and it only moves when a contract is opened or closed out. How the two differ, how traders read them together, where open interest is published, and what a price and volume screenshot can and cannot tell you.
Pull up a futures or crypto perp chart and the volume bars are right there under the candles. Open interest usually is not. It lives on the exchange's data page, in a quote panel, or in an indicator you have to add yourself. People mix the two up because both are counted in contracts and both get quoted as a measure of how busy a market is. They count different things. A day can trade 90 contracts and leave open interest exactly where it was.
Quick Answer
Volume is the number of contracts traded during a period: a bar, a session, a day. It is the bars under your candles, and it resets with every new bar. Open interest is the number of contracts still open at the end of the trading day. It carries forward, and it only changes when a contract is opened or closed out. A trade between someone opening and someone closing hands an existing position over, so it adds to volume and leaves open interest where it was. That is why volume can be huge on a day when open interest barely moves. Exchange futures publish open interest once a day, while crypto perpetual venues each do it their own way. Neither is printed on a normal candlestick screenshot unless you added it.
General education, not investment advice. No open interest or volume figure on this page is a live or current number. The contract counts in the diagram are invented so the arithmetic is easy to check.
What Is Open Interest?
Open interest is the count of derivative contracts that have been opened and not yet closed, settled or expired. The CME Group lesson on open interest defines it as the total number of futures contracts held by market participants at the end of the trading day, and it makes a comparison that helps: a company's share count stays roughly fixed, while the number of outstanding futures contracts changes every day.
That comparison is the whole idea. A share already exists before you buy it. A futures contract does not exist until a buyer and a seller agree to open one, and it stops existing when both sides close out or it settles. Open interest is the running count of contracts that currently exist. If the mechanics of a contract are new to you, the beginner's guide to how futures work covers margin, expiry and rollover first.
Three details trip people up. First, each open contract has a long on one side and a short on the other, and open interest counts the contract once. It is not longs plus shorts. Second, it counts contracts, not dollars, so a contract's size matters when you compare markets. A Micro E-mini and an E-mini are separate contracts with separate open interest figures, and the micro vs E-mini comparison shows how far apart their contract sizes are. Third, open interest belongs to derivatives. Plain shares have volume and a float but no open interest. (Options on a stock carry their own open interest, which is a separate topic this post does not cover.)
How Does Open Interest Change?
Every trade has a buyer and a seller, and each of them is either opening a new position or closing one they already hold. That gives three cases, and only two of them move open interest.
Both sides open: open interest rises
A new buyer goes long and a new seller goes short. A contract that did not exist now does. Volume goes up by one and open interest goes up by one.
One side opens, the other closes: open interest stays put
Someone who was long sells to close, and the buyer is opening a new long. The position changed owners, but the number of open contracts did not. Volume goes up by one. Open interest is unchanged. Most of the trading in a busy session can be this kind of handover, which is the main reason the two numbers drift apart.
Both sides close: open interest falls
A long sells to close and a short buys to close against each other. A contract stops existing. Volume goes up by one and open interest goes down by one. Forced closes count here too: shorts buying back into a rising price is the engine of a short squeeze and its forced-buying loop, and in futures those buybacks print as volume, and shrink open interest only when the seller on the other side is a long closing out too. If the seller is opening a fresh short, it is a handover and open interest does not move.
The diagram runs those rules over five made-up days. The bars are volume, the line is end-of-day open interest, and every number is computed from the trades listed under each day.
Illustrative only: five made-up days of volume and open interest
Look at Day 3. It traded 90 contracts, the biggest volume bar by far, and open interest ended exactly where it started at 15, because every trade was a handover. Day 4 traded only 14, yet open interest dropped by 8 to 7, since some of those trades closed both sides. Day 5 traded the same 14 contracts and open interest jumped to 17. The two volume bars are the same height, and the open interest moved in opposite directions, which the volume bars alone had no way to show.
Open Interest vs Volume, Side by Side
The two side by side, on the questions that come up when you are looking at a chart.
| Question | Volume | Open interest |
|---|---|---|
| What it counts | Contracts traded during a period (a bar, a session, a day) | Contracts still open at the end of the trading day |
| What changes it | Every trade, whether it opens, closes or hands over a position | Only a contract being opened or closed out |
| Resets? | Yes, every new bar and every new session starts from zero | No, it carries forward from day to day |
| One position traded back and forth | Counted every time it changes hands | Counted once while it stays open |
| Updates | Live, as trades print | Once a day for exchange futures, varies by venue for crypto perpetuals |
| Where you find it | The volume pane under the candles on almost any chart | Exchange data pages, some platforms' quote panels or an added indicator |
| On a normal candlestick screenshot? | Yes, if the volume pane is turned on and in frame | No, not unless you added it to the chart yourself |
| Exists for plain shares? | Yes | No, shares have a float, not open interest |
| Near expiry (dated futures) | Often moves to the next month as traders roll | The expiring month winds down toward zero |
The row that matters most for chart reading is the screenshot one. Volume is something you can see and compare bar by bar. Ratios like the one in the relative volume (RVOL) breakdown are built from it, and so is the running total in the on-balance volume guide, which adds a bar's volume on an up close and subtracts it on a down close. Both are computed from the volume pane. Open interest cannot be worked out from the chart at all, because the chart has no way of knowing whether each trade opened, handed over or closed a position.
How Do Traders Read Open Interest and Volume Together?
The usual shorthand is "new money vs position churn." If open interest is rising, more contracts are open than before, so positions are being added. If volume is heavy and open interest is flat or falling, on net, positions are being swapped or closed rather than added. The CME lesson linked above puts it in money terms: rising open interest as money moving into the contract, falling open interest as money moving out. It also describes analysts using rising open interest as confirmation of a trend.
Treat that as a convention many traders use, not as a tested signal. Open interest tells you that positions were added or removed. It does not tell you which side was the aggressive one, and every added contract has a new long and a new short behind it. The table below lists the labels you will see most often for open interest and volume combined with price, next to the other things that could produce the same numbers.
| What you see | Common label | What else could explain it |
|---|---|---|
| Price up, open interest up | New longs opening | Every added contract has a new short as well as a new long. OI shows that positions were added, not which side was pushing |
| Price up, open interest down | Short covering | Every contract that closed had a long selling and a short buying. The label assumes the shorts were in a hurry, and longs taking profit into strength produce the same numbers |
| Price down, open interest up | New shorts opening | New longs buying the dip sit on the other side of every new short. The label assumes the side moving price was the side opening |
| Price down, open interest down | Long liquidation | Same mechanics as the short covering row. Shorts taking profit into weakness fit too, and a front month near expiry loses OI whatever the direction |
| Big volume, open interest flat | Position churn | Day traders opening and closing inside the session add volume and leave nothing in the end-of-day count. It can also be a quiet market where existing holders are swapping out |
A few practical limits on top of the table. Open interest is a daily number for exchange futures, so it cannot tell you anything about the last hour of an intraday move. A position opened and closed inside the same session shows up in volume and leaves no trace in the end-of-day count, which matters if most of the activity you care about is day trading. And near expiry, the front month's open interest falls as traders roll, whatever price is doing, so a drop that week is often just the calendar. High open interest on its own is not bullish or bearish. It means a lot of contracts are open, which traders usually read as a sign of a deeper, more liquid market rather than a direction.
If you want a bar-by-bar read that does live on the chart, the volume spread analysis write-up compares each bar's volume (the effort) with its range and close (the result). That is a read of the volume pane itself, and it says nothing about open interest either.
The volume bars are on the chart. Get a second read on them.
Upload the chart screenshot and SnapPChart grades that single image as a momentum continuation setup, long or short: structure, EMAs, VWAP, MACD and the volume bars in frame, then an entry, a stop with its reasoning, and targets when the chart supports a trade.
Grade this chartWhere Is Open Interest Published?
Exchange futures: once a day
The CME lesson says open interest data is published at the end of each day, and CME publishes volume and open interest pages for its products, for example the E-mini S&P 500 volume and open interest page. Because the count is taken at the end of the trading day, the figure you see during a session is usually the previous session's. Futures sessions also do not line up with the stock market's day, which the guide to futures trading hours and the overnight session walks through, so check which session a daily figure belongs to.
The weekly breakdown by trader type
The daily figure is one number. For who holds the positions, the CFTC publishes the Commitments of Traders report. Its page about the COT reports says the reports break down each Tuesday's open interest for markets where 20 or more traders hold positions at or above the CFTC's reporting levels, and that the weekly futures reports are released every Friday at 3:30 p.m. Eastern. It is a weekly, delayed view, useful for the bigger picture and not for timing an entry.
Crypto perpetuals: depends on the venue
Crypto perps are different. Each venue runs its own book and decides how it reports open interest: many show it on the contract page and update it through the day, the unit can be contracts, coins or dollars, and data sites often add up several venues into one figure. There is no single official number the way there is for an exchange-listed future. The perpetual futures explainer covers the funding and liquidation side of the same contracts, which also live on the exchange and not on the chart.
Not on a normal candlestick screenshot
A standard chart shows price candles and, if you turn it on, a volume pane. Some platforms let you add an open interest line as an extra study, but it is not part of the default chart, and when it is added it is usually a daily line sitting under intraday candles. So unless you put it there, a screenshot of your chart contains price and volume and nothing about open interest.
What a Price and Volume Screenshot Can and Cannot Tell You
SnapPChart reads one chart screenshot you upload. That is the whole input. It does not see open interest, funding rates, liquidation data, the order book or any other exchange data, and it does not scan the market live. So the honest workflow has two steps. Check open interest yourself where it is published, if it matters to how you trade. Then upload the chart and get a read on what the picture shows.
What the picture shows is a lot. The grader reads structure and levels, the EMAs, VWAP, MACD and the volume bars in frame. The write-up on how AI reads volume off a chart goes into the volume part, including the useful habit of saying it cannot read volume when the pane is cropped off instead of inventing a number. It grades momentum continuation setups, long or short, the approach laid out in the momentum trading strategy guide, and does not take reversals. It returns a grade and one of three calls (take the trade, wait for a pullback, or skip it), and when the chart supports a trade, an entry, a stop with the reasoning behind its level, and targets.
What the picture cannot show is whether a volume spike was new positions or a handover. The screenshot does not contain that information. A big green bar on heavy volume is read as a big green bar on heavy volume, with no view into who opened or closed what. The grade is not an open interest read and not a win rate.
One more thing to know up front. Futures and crypto are among the instrument types graded on a scale capped at B, so a chart read as futures or crypto tops out at B. That is a deliberate guardrail because the scoring was built on stock momentum, not a judgement on your chart. The futures chart analysis page covers index, energy and metals futures charts like ES, NQ, CL and GC, the crypto chart analysis page covers coin charts, and the AI chart analysis page explains the screenshot grading in more depth.
Volume counts every contract traded in a period and lives on your chart. Open interest counts the contracts still open at the end of the day, moves only when contracts are opened or closed, and lives on the exchange. A handover trade adds volume and leaves open interest alone, so the two can disagree on any given day. Traders often read rising open interest as new money and heavy volume on flat open interest as churn, and that is a convention, not a signal. Check open interest where it is published, then use the chart for what the chart can show.
Frequently Asked Questions
Can open interest be higher than volume?
Yes, and on a quiet day it often is. Open interest is a running total of positions that were opened over many sessions and are still open, while volume only counts what traded in the current period. A contract with a lot of positions carried from earlier weeks can trade fewer contracts in a slow session than it has open. The reverse happens too: on a busy day, contracts can change hands many times, so volume can run well past open interest.
What happens to open interest when a futures contract expires?
Every position in the expiring month has to be closed, rolled or settled, so that month's open interest winds down toward zero as expiry gets close. Traders who want to stay in the market open positions in the next month, which is why open interest tends to shift from the front month to the next one around the roll. The total for the product as a whole may barely change while the per-month figures move a lot, so check which number your platform is showing.
Is open interest the number of traders, or longs plus shorts?
Neither. Every open futures contract has a long on one side and a short on the other, and open interest counts that contract once. It does not add the longs to the shorts, and it says nothing about how many people are behind the positions: one large trader can hold thousands of contracts, and a thousand small traders can hold one each. If you want a breakdown by type of trader, the CFTC's weekly Commitments of Traders report is where that lives.
Why does my platform show a different open interest number than the exchange?
A few common reasons. The platform may show the prior session's figure while the exchange page has a newer one, or the other way around. It may show one contract month while the exchange shows the total, or a sum across months. For crypto perpetuals, a data site may add up open interest across several venues, and venues count it differently (in contracts, in coins or in dollars). Match the source, the contract and the unit before comparing two numbers.
Does SnapPChart read open interest?
No. SnapPChart reads the chart screenshot you upload and nothing else. Open interest is not printed on a normal candlestick chart, so it is not in what the grader sees. It does not pull exchange data, funding rates, liquidation data or the order book, and it does not scan the market live. If open interest matters to your read, check it on the exchange or your platform before you upload, and treat the grade as a read of the price and volume bars in the picture.
This article is for educational and informational purposes only and is not investment, financial or trading advice. The definition of open interest as the total number of futures contracts held at the end of the trading day, the comparison with a company's share count, the description of rising and falling open interest as money moving in and out, the note that analysts use it to confirm trends, and the statement that open interest data is published at the end of each day are from the CME Group lesson on open interest. The Tuesday as-of date, the 20-trader threshold and the Friday 3:30 p.m. Eastern release time are from the CFTC page about the Commitments of Traders reports. Both were read in October 2026. The descriptions of how individual trades change open interest, expiry and roll effects, and how crypto venues report open interest are general knowledge. Each exchange and venue sets its own rules, so check the source before relying on a figure. No open interest or volume number here is a live, current or typical figure, and the contract counts in the diagram are invented so the arithmetic can be checked. The price and open interest labels are a common reading convention, not a tested signal, and no statistic, win rate or return is claimed for them. SnapPChart grades a static chart screenshot you upload and returns a setup grade, a call and, when the chart supports a trade, an entry, stop, targets and reasoning for that single image. It grades long and short momentum continuation setups only, does not take reversals, caps futures and crypto grades at B, and does not see open interest, funding rates, liquidation data, the order book or any exchange data.
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Check open interest on the exchange, then grade the chart.
Check open interest where it is published first. Then upload the chart screenshot and SnapPChart grades that one image as a long or short momentum continuation setup: a grade, a take, wait or skip call, and when the chart supports a trade, an entry, a stop with its reasoning, and targets. A chart read as futures or crypto is graded on a scale capped at B. One skipped bad entry covers it.