Relative Volume (RVOL): What It Measures, and the Screenshot Version You Can Read Yourself
Relative volume is current volume divided by average volume, a ratio that tells you whether a stock is busier or quieter than its own normal. The formula, how to read 1.0, 0.5 and 2.0, why the lookback and time of day change the number, the thresholds sources cite and where they disagree, pre-market use, the failure modes, and the honest version you can read off a chart screenshot.
Relative volume is the number most momentum scanners sort by, and it is one of the simplest ratios in trading. Take the volume a stock is doing now, divide it by the volume it normally does, and you get a figure that says whether today is unusual for that particular stock. The arithmetic takes one line. The arguments start right after it: average over how many days, measured at what time of day, and how big a ratio counts as interesting. None of those have one agreed answer, and the platform you use has already picked for you.
Quick Answer
Relative volume (RVOL) = current volume / average volume over a lookback period. A reading of 1.0 means the stock is trading its normal amount, 2.0 means double, 0.5 means half. The lookback is a choice, usually 10 to 20 days, and platforms differ. Good intraday versions compare volume so far today with the average at the same clock time, because the open and close are always busier than midday. Many sources cite 2.0 as the level where a stock is "in play", but they disagree above that and none of them is a rule. RVOL measures participation, not direction, and it misleads on news spikes, thin low-float names and late-stage climax moves.
Below is each of those pieces in turn, then the part most explainers skip: what you can and cannot get from a chart screenshot, where there is no RVOL column, only a volume pane.
What Is Relative Volume in Stocks?
Relative volume compares a stock's current trading activity with its own recent baseline and expresses the result as a ratio. Every reference I read writes the formula the same way. The StockCharts ChartSchool entry on Relative Volume (RVOL) defines it as current volume divided by average volume over the look-back period, and Centerpoint Securities' explainer on relative volume in stocks works an example where the average is simply the total of the last 10 days divided by 10.
RVOL = current volume / average volume over N periods
Reading the number
1.0 is normal. Above 1 is busier than usual, below 1 is quieter. A hypothetical stock that averages 2,000,000 shares a day over the last 10 sessions and trades 3,000,000 today finishes at 1.5. If it trades 1,000,000 it finishes at 0.5, half its usual activity. At 6,000,000 it is at 3.0. The ratio has a floor of zero and no ceiling, and on a heavy news day you will see double-digit readings on names that normally trade quietly.
The lookback is a choice
The N in the formula has no standard. IG lists five, 10, 30 and 60-day periods as typical. Tradingsim uses 10 to 20 days. StockCharts defaults to a 50-period moving average you can change, and TrendSpider's worked example averages the last 50 bars. A shorter window reacts faster and gets pushed around by one recent big day. A longer window is steadier and slower to notice that a stock's normal has changed. If you remember one thing, make it "typically 10 to 20 days, and your platform may differ", because the same stock on the same afternoon could read, say, 1.6 on one screen and 2.4 on another purely from the lookback.
Average volume, by the way, is not a competing metric. It is the denominator. When someone says a stock has "high volume" and means high average volume, they are describing liquidity. When they say high relative volume, they mean today is unusual against that average. A liquid mega cap can have huge average volume and an RVOL of 0.7 on a sleepy Tuesday.
Why Does the Time of Day Change the Number?
Intraday volume is not spread evenly. US stocks typically trade heavily in the first stretch after the open, thin out through midday, and pick up again into the close, so a chart of volume by time of day looks like a U. That shape breaks the naive formula in two opposite ways, depending on what you divide by.
Take the same hypothetical stock, averaging 2,000,000 shares a day. It is 10:00 and it has traded 900,000 so far.
Cumulative volume vs the full-day average:900,000 / 2,000,000 = 0.45. That reads as a dead stock, which is absurd half an hour into the session. Every stock looks quiet in the morning on this method because the day isn't finished.
One bar vs the average bar of the day: say the first 5-minute bar traded 250,000. A full day is 78 five-minute bars, so the average bar is about 25,600 shares. 250,000 / 25,600 is roughly 9.8. That reads as a huge event, and it is just the open, which is always heavy.
The time-of-day version:compare volume so far today with the average volume this stock had traded by 10:00 on each of the prior 10 or 20 sessions. If that average is 600,000, today's 900,000 gives 1.5. That is the number you actually want: busier than its usual 10:00, by half. Tradingsim describes this same-clock-time comparison over the past 10 to 20 sessions, and StockCharts calls its version RVOL-TOD. Scanners that rank stocks by RVOL during the session generally need some form of it, or the list is just whatever opened.
Illustrative only: two different relative volume reads
The practical consequence: a 2.0 at 9:45 and a 2.0 at 3:30 are not the same statement unless your platform is adjusting for time of day. If it isn't, the morning number is distorted in one direction or the other, depending on the method.
Relative Volume vs Raw Volume vs OBV
Raw volume is the share count. It is the thing printed under each candle, and it means very different things on different stocks. A mega cap trading 40 million shares might be having an ordinary day. A small cap trading 400,000 shares might be having the busiest session of its year. RVOL exists to fix exactly that, by dividing each stock by its own normal so the readings become comparable. The flip side, which TrendSpider points out, is that RVOL tells you nothing about absolute levels. A 5.0 on a name that usually trades 50,000 shares is still only 250,000 shares, and you may not be able to get in and out of a real position there.
The third volume tool people mix these up with is On-Balance Volume, a signed running total that answers a different question entirely. The OBV breakdown covers how that cumulative line is built and read, so here it only appears for contrast.
| Dimension | Raw volume | Relative volume (RVOL) | On-Balance Volume |
|---|---|---|---|
| The question it answers | How many shares traded in this bar or session? | Is this stock busier or quieter than its own normal right now? | Has volume been net positive or net negative by the close-to-close test over a stretch of bars? |
| Input needed | The volume for the period. Nothing else | Current volume plus a history of the same stock to average. Ideally the average volume at the same clock time | Each bar's close and volume, accumulated from wherever the chart starts |
| Comparable across stocks? | No. 2 million shares is a dead day for one name and a frenzy for another | Roughly, yes. A ratio of 3 means three times normal on any stock, which is the reason it exists | No. The level depends on the anchor point, so only the slope reads |
| Does it carry direction? | No, though platforms color the bar by the candle | No. It measures participation only | Yes, by construction. Every bar is signed by its close |
| Readable on a static screenshot? | Yes, if the volume pane is in frame | Only if the platform prints it. Otherwise you get a rough bar-vs-visible-bars comparison | Only if you plotted it before taking the screenshot |
| Typical misuse | Comparing share counts between a mega cap and a small cap and calling one 'heavy' | Treating a high reading as a buy signal, or reading an unadjusted morning number as if it were the full day | Quoting an OBV level as bullish, or comparing OBV values between two charts |
| Where it breaks | Any comparison without a baseline | News spikes, thin and low-float names, holiday sessions, pre-market's small sample | One-off spike days that step the total permanently, gap-heavy charts, flat closes |
The row worth rereading is the screenshot one. Raw volume is sitting right there in the volume pane. RVOL isn't, unless your platform happens to print it as text on screen. That gap matters later. If you want the other volume views covered properly, there are separate write-ups on volume profile and where volume clusters by price and on reading volume against the spread of each bar.
What Is a Good Relative Volume?
There isn't one, and the honest way to show that is to put the sources side by side. The most repeated figure is 2.0, double normal volume, as the point where a stock counts as "in play". Above that the bands drift apart: some sources call 3.0 a catalyst marker, some put the spike line at 4.0, others at 5.0, and one suggests the useful zone stops well short of 10. Here is what each of the pages I read actually says.
| Source | What it says about levels | Lookback or context |
|---|---|---|
| StockCharts ChartSchool | 1.0 is the baseline. Many day traders look for over 2.0. Anything over 4.0 is a volume spike, and a spike while the stock is overbought or oversold could foreshadow a reversal | Default lookback is a 50-period moving average, adjustable |
| IG | Some traders want RVOL at least above 2.0, or double normal volume, before calling a stock in play | Lists five, 10, 30 and 60-day lookbacks as typical |
| Tradingsim | Above 1.5 is generally considered elevated, at least 2.0 for day traders, a higher bar for swing trades, and above 3.0 often points to a major catalyst | Uses 10 to 20 days, and describes the same-time-of-day intraday comparison |
| Trade Ideas | Unusual once RVOL exceeds two or three. Suggests the best edge sits between two and five, not above ten | Gives a sample scan pairing RVOL above two with a price and average-volume floor |
| TrendSpider | Above 1 is higher than average, below 1 lower. Gives a 1.5 worked example and no 'good' level | Example uses a 50-bar average |
| Centerpoint Securities | Explains 5 as five times average and 0.5 as half. No 'good' level given | Example divides by a 10-day average |
Two of the six don't give a "good" level at all, and that is worth noticing. The four that do agree on roughly 2.0 as a floor for attention and disagree on everything above it. They also disagree on what the label means. Some treat 2.0 as a filter that gets a stock onto your watchlist, others treat higher readings as evidence of a catalyst. A filter and a signal are different jobs. I didn't find a source that publishes a reproducible success rate for any threshold, so treat any number you adopt as your own filter setting, tuned to the stocks you trade.
Where RVOL earns its place is as one condition among several in a momentum setup. The momentum trading playbook uses unusual volume to decide what to watch, then relies on levels and structure to decide what to trade. And for the specific case of volume on a breakout candle, the breakout grading write-up covers how the break bar's volume gets weighed against the level and the trend, so I won't repeat it here.
The stock is trading three times its normal volume. That gets it onto your screen. It does not make the setup good.
Upload the screenshot and SnapPChart grades that single image against a fixed rubric: structure, levels, trend, the volume bars in frame, then an entry, a stop with its reasoning, targets and the reward-to-risk they imply. A C grade on a busy tape is still a C.
Grade this chartHow Is Relative Volume Used Pre-Market?
Mostly to find gappers. Before the open, traders scan for stocks that are already active on news, and volume is the quickest tell. IG's guide to the relative volume indicator notes that traders look at pre-market volume to see which stocks may already be trading heavily, and Trade Ideas' page on high relative volume stocks suggests using pre-market RVOL, where your tools offer it, for gap names. This is the front end of a gap-and-go workflow: find the stock that is gapping with real participation, mark the pre-market high, and see whether the open holds. The gap-and-go strategy page walks through the hold-versus-fade decision itself.
The caution is about sample size. Pre-market volume is thin, so the baseline is a small number, and a small number in the denominator produces big ratios from modest share counts. A hypothetical stock that normally trades 20,000 shares before the open and trades 200,000 this morning shows 10x, on a volume that disappears inside the first minute of the regular session. Pre-market RVOL is a good way to build a list. Whether the interest is real gets answered after 9:30, when the regular-session numbers either confirm it or don't.
Where Relative Volume Misleads
It measures participation, not direction
Most of the sources I read agree on this one. A 4.0 can be buyers piling in or holders dumping. The ratio is the same. Tradingsim says plainly never to assume high RVOL automatically means a buy signal, StockCharts says the indicator is meant to be used with other analysis rather than on its own, and TrendSpider says it should not be used in isolation. Centerpoint adds the mechanical reason: RVOL does not show the balance between buyers and sellers, and a few very large trades can inflate it. Price tells you direction. RVOL tells you how many people showed up to argue about it.
News and catalyst spikes
Earnings, an FDA headline, an offering, a halt and resume. All of these produce enormous readings, and many of them reverse inside the same session. IG flags false breakouts and pump-and-dump risk on high-RVOL names, and TrendSpider notes readings get pushed around by news and macro events. The RVOL on a news day tells you the stock has attention. It cannot tell you whether the news is good enough to hold the move, or whether everyone who wanted in is already in.
Thin and low-float stocks
On a stock that normally trades very little, a modest burst of shares produces an extreme ratio. A low float makes it worse, because a small supply of shares can move hard on that burst and halt. Trade Ideas specifically warns about ignoring float on extreme-RVOL small caps. Hypothetically, a 12x on a large cap and a 12x on a thin small cap are not the same event, and the second one can gap through your stop. This is the same problem covered from the scalping side on the scalp trading page, where spreads and fill quality decide whether a fast move is tradeable at all.
Climax and chasing
Very high readings late in a move can mark the end of it. StockCharts calls anything over 4.0 a spike and says a spike while the stock is overbought or oversold could foreshadow a reversal. Trade Ideas puts the useful zone between two and five rather than above ten, and warns that declining RVOL into new price highs points to exhaustion. Say you find a stock at 15x after it has already run 80%. The ratio is describing the crowd that made the move. Buying there means you are the crowd's exit.
The Screenshot Version You Can Read Yourself
This is the part that matters if you grade setups from chart images, including with SnapPChart. A screenshot holds the candles and volume bars that were drawn on screen when you took it. That is all. There is no 10-day history in the file, no record of what this stock had traded by 10:00 on the last 20 sessions, and usually no axis precise enough to read exact share counts. So a screenshot cannot give you true RVOL, and it definitely cannot give you the time-of-day version. Your platform or scanner computes that, from data the image doesn't contain.
What a screenshot does give you is a comparison inside the frame. Look at the volume bar under the candle you care about, then look at the other volume bars visible. Is the breakout bar twice as tall as everything around it? Are the pullback bars shrinking? Is there one huge red bar sitting at the level you want to buy? That is a relative-volume read in the loosest sense: this bar relative to its neighbours on this chart. It is useful, and it is a different measurement from the RVOL number on your scanner. The right panel of the diagram above is exactly this.
That in-frame comparison is how SnapPChart handles volume. It reads the volume bars drawn in the uploaded screenshot and compares each one with the others visible, and bars that stand out at roughly double the visible average or more get flagged and weigh into the grade. A big counter-direction volume bar anywhere in frame counts heavily against the setup, for example. It does not read or calculate your platform's RVOL value, it does not scan the market for high-relative-volume stocks, and it has no live data, pre-market volume or float figures. Which chart features a single image genuinely carries is covered in the guide to how AI reads a chart, and the piece on AI volume analysis for momentum trades goes deeper on reading those volume bars. A neutral description of what one chart read covers is on the AI chart analysis page.
So the workflow splits cleanly. The scanner finds stocks with unusual relative volume. The screenshot grade looks at one of them and asks whether the structure, the levels and the volume visible on that chart add up to a trade, which is the job described on the momentum trading AI page. Picking which volume read belongs where is part of the bigger question of which indicators earn space on an intraday chart, and the technical analysis overview puts volume alongside the rest.
RVOL is current volume divided by average volume. 1.0 is normal, 2.0 is double. Find out what your platform divides by, because lookback and time-of-day adjustment change the number more than most people expect. Treat 2.0 as a common watchlist filter, not a trigger, and know that sources disagree on everything above it. Use it to find stocks, use price to decide trades, and be suspicious of extreme readings on news, on thin names and late in a run. On a screenshot, you can compare one volume bar against the others in frame. The real ratio comes from your platform.
Frequently Asked Questions
Why does my RVOL number differ between two platforms?
Because there is no single RVOL. One platform might divide today's cumulative volume by a 10-day daily average, another might use a 50-period moving average of bars, and a third might compare against the average volume at the same clock time over the last 20 sessions. Add in whether extended-hours volume is counted and whether the average skips earnings days, and two screens could show, say, 1.8 and 3.1 for the same stock at the same minute without either being wrong. Before you compare numbers, find out what each one is dividing by. The settings page usually tells you, and if it doesn't, assume the two numbers are not comparable.
Can you use relative volume on a daily chart for swing trades?
Yes, and on a daily chart the time-of-day problem disappears once the session closes, because you are comparing one finished day with other finished days. Tradingsim mentions a separate, higher bar for swing traders than for day traders, which tells you the same ratio gets read differently depending on the holding period. The daily version is mostly used after the close to spot names where participation stepped up, then you wait for a level and a trigger the next session. Reading a daily RVOL figure at 10:30 in the morning puts you right back into the partial-day problem, so check whether your screen is showing a projected or a running number.
What does an RVOL below 1 tell a day trader?
That the stock is trading less than it usually does. For a momentum trader that is mostly a reason to look elsewhere, since the whole point of the filter is to find stocks people are paying unusual attention to. It is not automatically bearish. A pullback on below-average volume inside an uptrend is something a lot of traders actually want to see, because it suggests the selling is light. So below 1 on the session is a filter result, and below-average volume on specific pullback bars is a pattern read. Those are two different questions using the same word.
Can AI calculate relative volume from a chart screenshot?
Not true RVOL. A screenshot holds whatever bars were drawn in the image and nothing else, so there is no prior-session history at the same clock time, no 10-day or 20-day average, and often no axis precise enough to read exact share counts. What an image does allow is a comparison inside the frame: is this volume bar large or small next to the other volume bars visible. If you want the real number, read it off your platform or scanner. SnapPChart does not read an RVOL value from the image. It only compares the volume bars in frame with each other, and the grade reflects that comparison.
Is relative volume a leading indicator?
It is a current-state measure with a lagging denominator. The numerator is volume that has already traded, the denominator is an average of sessions that already happened, so nothing in it forecasts. What makes people call it leading is that unusual participation often shows up around the time a stock starts moving, so a scanner sorting by RVOL surfaces names early in the move. That is a sorting benefit. A high reading tells you attention has arrived. It does not tell you which way price goes next, and the sources that cover it are consistent on that point.
This article is for educational and informational purposes only and is not investment, financial or trading advice. The relative volume formula, the lookback periods, the time-of-day variant and the threshold levels described are as stated by the cited sources (StockCharts ChartSchool, IG, TrendSpider, Tradingsim, Trade Ideas and Centerpoint Securities) and are reproduced as their published descriptions, not as rules endorsed here. Every worked example, including the 2,000,000-share average, the 10:00 cumulative figures, the opening-bar figure and the pre-market example, is a hypothetical construction built so the arithmetic can be checked; none is a real security or a real session. The diagram is illustrative and not drawn from market data. No success rate, win rate or backtest is claimed for any relative volume threshold, and none is implied. Volume readings describe activity that has already happened and do not predict direction. Day trading carries a substantial risk of loss and is not suitable for every investor. SnapPChart grades a static chart screenshot you upload and returns a setup grade, entry, stop, targets and reasoning for that single image; it compares the volume bars visible in the image with each other, and does not calculate a platform's relative volume value, does not scan the market, does not use live, pre-market or float data, and does not track your account, positions or P&L. Do your own analysis, size positions so that being wrong is survivable, and consider speaking to a licensed financial professional about your own circumstances before trading.
Writes about AI-assisted day trading, technical analysis, and the systems traders actually use to stay disciplined.
High relative volume tells you the stock is in play. It says nothing about whether your entry is any good.
Upload the chart screenshot and SnapPChart grades that one image against a fixed rubric, including how the volume bars in frame compare with each other, then returns a setup grade, an entry, a stop with the reasoning behind the level, targets, and the reward-to-risk they imply. Skipping one bad trade on a busy tape covers it.