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Key Takeaways
- RVOL gives raw volume context by dividing it by a clearly defined historical average.
- Intraday RVOL should compare equal elapsed times because cumulative volume follows a strong time-of-day pattern.
- An RVOL of 2.0 means twice the baseline volume; price movement and liquidity need their own reads.
- Use RVOL to rank activity, then define direction from the price setup and trading rule.
- Rank a watchlist on one setting: the same session hours, the same time of day and the same volume source for every ticker.
What is relative volume (RVOL)?
Relative volume (RVOL) is a ratio that divides a security’s current trading volume by a historical baseline for the same security, such as its average volume through the same time of day over the prior 20 sessions. A reading of 1 matches the baseline and a reading of 2 is twice the baseline, so the ratio can rank activity across a watchlist.
RVOL turns a raw share count into context. It measures volume only, so an RVOL of 2.0 means twice the baseline volume, and price movement and liquidity need their own reads. Choose the period and volume coverage before comparing tickers.
Intraday vs full-session RVOL
Completed-session RVOL compares a full session with prior full sessions. Time-adjusted intraday RVOL compares cumulative volume through the current time with the historical average through that same time.
The example averages the prior 20 regular sessions and leaves the current one out, so today’s surge cannot inflate its own baseline. Keep session hours and the volume source consistent.
A bar-based version compares one bar’s volume with the same bar’s historical average, which catches a single burst that a cumulative reading smooths over.
Formula
RVOL = current volume / average comparable-period volume- For an intraday reading, compare volume through the same time of day across prior comparable sessions.
- The baseline is the average volume through the same time over the prior 20 regular sessions, with today left out so the current move cannot inflate its own baseline.
How to calculate RVOL: 11:00 a.m. example
At 11:00 a.m., a stock has traded 1.8 million shares. Its average cumulative volume by 11:00 a.m. over the prior 20 regular sessions is 750,000 shares.
- 1,800,000 / 750,000 = 2.40 RVOL
- 1,800,000 − 750,000 = 1,050,000 shares above the baseline
- 2.40 − 1.00 = 1.40, or 140% above average comparable volume
At 11:00 a.m., 1.8M shares divided by the 750,000-share equal-time baseline gives 2.40× RVOL. Activity is 140% above that baseline, an excess of 1.05M shares.
Why RVOL can fall while volume rises
Both the numerator and denominator grow through the session. At 4:00 p.m. in the chart, current volume is 4.8M shares and the baseline is 3M, giving 1.60× RVOL.
Current cumulative volume rose from 1.8M to 4.8M while RVOL fell from 2.40 to 1.60. The baseline increased proportionally faster over that interval.
A falling ratio on rising volume means the afternoon traded closer to its usual pace than the morning did.
How traders use relative volume
Rank your watchlist by RVOL, then inspect the catalyst, price structure, spread and the size you intend to trade. A 6× ratio on a 20,000-share baseline equals 120,000 shares; a 2× ratio on a 20M baseline equals 40M shares.
Define the price trigger, invalidation, position size and exit. Use Volume Profile to examine where volume traded across prices and VWAP for a volume-weighted price reference. Options Flow shows whether the volume surge reaches the options, with sweeps, blocks and size against open interest, and the Options Profit Calculator prices each structure at your target and expiration.
Limitations of relative volume
- Take direction from price. RVOL shows how unusual activity is, and a high reading can accompany a rally or a selloff.
- Check the share count behind the ratio. A 6× reading on a 20,000-share baseline is 120,000 shares, far fewer than a 2× reading on a 20M baseline.
- Match the settings before comparing platforms. The lookback, averaging rule, session hours and volume source all move the value, so line them up before you read one screen’s RVOL against another’s.
- Compare intraday readings at the same time of day. Both totals grow through the session: in the chart, RVOL falls from 2.40 at 11:00 a.m. to 1.60 at the close while volume keeps rising.
- Check the baseline window for outlier sessions. A heavy-volume session inside it, such as an earnings day, raises the average and lowers later readings.
Bottom line
Relative volume shows how unusual current trading activity is against a stock’s own history. Use an equal-time baseline for intraday readings, check the share count behind the ratio, and take direction from the price setup, since RVOL measures participation rather than which way price will move.
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Sources and Further Reading
How entries are sourced, calculated and updated: editorial methodology.