What Is Trading Volume? How Volume Is Counted and Read on a Chart

Trading volume is the number of shares or contracts that change hands in a market over a set period, such as a day; each trade is counted once, not per side.

Volume is the bar chart that runs along the bottom of most price charts, and one of the few numbers that describes how much trading took place rather than at what price. This page covers what volume counts and what it does not, why every share bought is also a share sold, how volume is drawn on a chart, a worked example comparing a stock's daily volume with the off-exchange slice that FINRA publishes, how volume differs from open interest and from liquidity, and where the volume in Kresmion's charts comes from, including the markets that have none. It is descriptive throughout.

What volume counts

Nasdaq's glossary defines volume as the daily number of shares of a security that change hands between a buyer and a seller. The CFTC's glossary gives the futures version: the number of contracts traded during a specified period of time. The period can be anything a chart uses, from one minute to one month, and the volume for that bar is the total traded inside it.

Because a share changes hands from a seller to a buyer, one trade of 100 shares adds 100 to the volume, not 200. Volume is counted in units of the thing traded: shares for a stock, contracts for a future or an option, coins for a crypto asset. Multiplying by the price gives dollar volume, the value traded, which makes a busy day in a $5 stock comparable with one in a $500 stock.

Every share bought is a share sold

A common reading of a heavy-volume day is that there were more buyers than sellers. Volume cannot show that. Each share traded had exactly one buyer and one seller, so the number of shares bought and the number sold on any day are equal by definition.

What differs from trade to trade is which side was in a hurry: whether the buyer crossed the spread to take the seller's resting offer, or the seller crossed to hit the buyer's resting bid. The resting and crossing roles are described in market order vs limit order. Volume on a chart counts both kinds together, so a rising price on high volume says that many shares traded while the price rose, not that buyers outnumbered sellers.

How volume appears on a chart

Most charts draw volume as a histogram: one vertical bar per period, its height the number of shares or contracts traded in it, drawn either along the bottom of the price pane or in a pane of its own. Many colour each volume bar to match its price bar, for example green when the period closed at or above its open and red when it closed below. The colour describes the price bar; it does not split the volume into buying and selling.

Volume is also an input to other measures. VWAP weights each price by the volume traded at it. On-balance volume adds a day's volume to a running total when the close rises and subtracts it when the close falls. A volume profile adds up how much traded at each price rather than in each period.

A worked example: one stock, two volume numbers

On 30 September 2026, the daily bar for Apple (AAPL) in Kresmion's price history feed showed 49,931,500 shares traded.

FINRA publishes a second number for the same day. Its daily short sale volume files cover trades reported to FINRA's off-exchange reporting facilities during normal market hours, and the figures Kresmion uses, the same as FINRA's combined TRF and ADF file, cover trades in exchange-listed securities reported to FINRA's trade reporting facilities and its Alternative Display Facility (ADF). In Kresmion's copy of that data for 30 September 2026, which matches FINRA's file for the day, AAPL's total reported volume was 15,902,818 shares, of which 6,527,109 were short sales. The short-volume ratio, short volume divided by that total, was 6,527,109 / 15,902,818 = 41.0 percent.

The two totals are not in conflict. FINRA's file counts only trades reported to those off-exchange facilities during normal market hours; trades executed on exchanges such as Nasdaq or the NYSE are not in it, and the price feed's daily figure comes from a different source with its own counting rules. So the FINRA total is the smaller number, and the 41.0 percent ratio describes off-exchange reported trades only. The short-volume ratio measures a daily flow, not the number of shares held short, which is short interest; what short volume is covers the difference.

Kresmion's public off-exchange short volume tool, free with no account, shows the latest FINRA day for each covered symbol, ranked by default among symbols with at least 100,000 shares traded off-exchange: short volume, off-exchange volume, the short-volume ratio, and how far the ratio sits from the symbol's own 20-session average.

Volume, open interest and liquidity

Volume and open interest. In futures and options, volume counts contracts traded during the period, while open interest counts contracts still open at the end of it. A trade between one trader opening a position and another closing one adds to volume and leaves open interest unchanged. What open interest is walks through every case.

Volume and liquidity. Heavy volume is one sign that a market is easy to trade, but it is not the same thing as liquidity at a given moment. What an order pays to trade now depends on the gap between the best bid and the best offer and on how many shares rest at each price, described in the bid-ask spread. A stock can trade millions of shares in a day and still have a thin book in the minute an order arrives.

Relative volume. A volume figure means little without a comparison. Analysts often set a day's volume against the same market's own recent average, since a quiet day for one large stock can be a busy month for a small one.

Volume in Kresmion's charts

Kresmion's charting workspace draws volume as a histogram along the bottom of the price pane. It is on by default and can be switched off with the Vol button in the toolbar or the V key. Each volume bar takes its colour from its price bar: the up colour when the bar closed at or above its open, the down colour otherwise. The Indicators menu adds volume-based measures, among them On-Balance Volume, the Money Flow Index, Chaikin Money Flow, a Volume Profile that marks the price with the most volume traded, VWAP and a volume-weighted moving average.

What the bars count depends on the market:

• Stocks and ETFs. The figure supplied by Kresmion's price feed for each bar, in shares, as in the Apple example.
• Crypto pairs. The volume on a single major exchange for the coin's pair against the USDT stablecoin, counted in units of the coin. It is not the total traded across every crypto exchange, and when that exchange has no pair for a coin the chart falls back to a price-only series with no volume.
• Spot currency pairs. None. Kresmion's price feed carries zero volume for spot FX pairs such as EUR/USD, GBP/USD and USD/JPY, so the chart draws no volume bars and volume-based indicators have nothing to work with.

The charts open with an account, which is free during the beta.

Honest limitations

A volume figure is only as complete as the venues behind it. Stock volume from one feed and the FINRA off-exchange file count different sets of trades, crypto volume in Kresmion's charts covers one exchange, and spot currencies carry none. Volume says how much traded, not who initiated the trades or why, and nothing on this page describes what volume implies for the next price. The Apple figures are one day's values from the sources named, read on 1 October 2026.

Key takeaways

Frequently asked questions

What does high trading volume mean?

It means many shares or contracts changed hands in the period, compared with whatever it is measured against, usually the same market's own recent average. It does not say whether buyers or sellers were more eager, since every share bought was also sold, and it does not by itself indicate what the price does next.

Does volume count both the buy and the sell?

No. A trade of 100 shares has one buyer and one seller and adds 100 shares to volume. Counting both sides would double every trade.

Why is there no volume on currency charts?

Because the spot FX bars in Kresmion's price feed carry zero volume, Kresmion's charts draw no volume bars for pairs such as EUR/USD, and indicators built on volume, such as VWAP, have nothing to compute. Other platforms may show a volume figure for currencies from their own venue or broker data.

What is the difference between volume and short volume?

Volume counts all shares traded. Short volume, as published by FINRA, counts the shares sold short within the trades reported to its off-exchange facilities on a given day. It is a daily flow, and it is different again from short interest, the number of shares held short at a point in time.

Is crypto volume on Kresmion the whole market?

No. The volume bars on Kresmion's crypto charts come from one exchange's trading pair against the USDT stablecoin, so they show the trading on that venue, not across every exchange that lists the coin.

This page is information, not investment advice.

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Source: Nasdaq, Glossary: Volume, https://www.nasdaq.com/glossary/v/volume ; CFTC, Futures Glossary, https://www.cftc.gov/LearnAndProtect/AdvisoriesAndArticles/CFTCGlossary/index.htm ; FINRA, Daily Short Sale Volume Files, https://www.finra.org/finra-data/browse-catalog/short-sale-volume-data/daily-short-sale-volume-files ; StockCharts ChartSchool, On Balance Volume (OBV), https://chartschool.stockcharts.com/table-of-contents/technical-indicators-and-overlays/technical-indicators/on-balance-volume-obv ; Kresmion price history feed, AAPL daily bar for 30 September 2026, read 1 October 2026 ; Kresmion copy of FINRA Reg SHO daily short sale volume, AAPL, trade date 30 September 2026, matching FINRA's consolidated file, https://cdn.finra.org/equity/regsho/daily/CNMSshvol20260930.txt ; Kresmion chart engine (volume histogram and volume indicators).

Kresmion Research.