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Relative Volume (RVOL)

// today's volume divided by the average volume at the same time of day

Relative Volume (RVOL) is the ratio of today's cumulative share volume to the average cumulative share volume at the same time of day over a recent lookback window. RVOL of 2.0 means today is running at twice the typical pace.

// TL;DR
  • Time-of-day-aware. RVOL at 10:00 ET compares against the typical 10:00 ET cumulative volume, not the typical close-of-day total.
  • Standard lookback is 20 sessions (one trading month). Some scanners use 10 or 30.
  • RVOL above 2.0 in the first hour is a common gappers-and-movers screener filter. Above 5.0 is unusual.

How it is calculated

RVOL(t) = cumulative_volume_today(t) / avg(cumulative_volume(t)) over lookback N sessions t is the current time of day. N is the lookback in sessions (Tapeboard default: 20).

The cumulative-volume comparison is what makes RVOL useful. Comparing absolute share count at 10:00 ET against the daily total for the prior 20 sessions would always look small; comparing against the 10:00 ET running total gives a regime-comparable number. The lookback excludes today.

What traders use it for

Worked example

// WORKED_EXAMPLE: $TSLA
RVOL on $TSLA after an earnings gap

Suppose at 10:30 ET the cumulative TSLA volume is 18.4M shares. The 20-session average cumulative volume at 10:30 ET is 6.1M shares. RVOL prints 18.4 / 6.1 = 3.02. As of 2026-05-02 10:30 ET. The session opened on a +4.2% earnings gap; an RVOL of 3.0 in the first hour is consistent with institutional reposition rather than a fade.

Live data: /stocks/TSLA.

Common pitfalls

Where this metric appears on Tapeboard

RVOL renders on /scanner (sortable column), on every `/stocks/{T}` ticker page, and as a screener-preset filter (e.g., "Top RVOL gappers" preset).

Tapeboard surfaces this metric as a first-class screening filter. See the comparison pages at all Bloomberg alternatives for how Tapeboard's relative volume (rvol) surface compares against Koyfin, Finviz, TradingView, and Unusual Whales.

Related terms

Primary sources cited

Methodology last reviewed 2026-05-04 by Marcus Reilly, Editor at Tapeboard. Every claim on this page has a row in the citation registry. Glossary terms reverify on the Jan 15 / Apr 15 / Jul 15 / Oct 15 cron and any time the underlying primary-source publishes a methodology change. See methodology for the full fact-check process and corrections for the public correction log.

Disclaimer. This page is for educational and informational purposes only. Nothing on Tapeboard is investment advice. See the full risk disclaimer.