Trading glossary
Trading volume
By the PatternX team · Published
Definition
Trading volume is the number of shares, contracts or coins that change hands in a given period, such as one candle or one day. It shows how much participation stands behind a price move.
How it's measured
Volume is counted per bar, so a 5-minute chart shows the units traded in each 5-minute window. Raw numbers vary enormously between markets, so traders compare volume with its own recent history:
A ratio of 2.0 means twice the recent norm. When the comparison is with a typical full day, the measure is usually called relative volume. Dollar volume (shares × price) is useful for comparing liquidity across instruments with very different prices.
Two caveats: crypto volume is split across many exchanges, so one venue's figure shows only part of the market, and stock volume in extended hours is usually much thinner than during the regular session.
Why it matters
Volume tells you whether a price move has participation behind it. A breakout on heavy volume is generally treated as more convincing than one on light volume, because it suggests real buying or selling rather than a few orders pushing a thin market. Volume that dries up during a consolidation and expands on the breakout is the classic textbook sequence. Heavy volume still doesn't tell you which side will win next.
Example
For example, suppose a stock has averaged 300,000 shares per 15-minute bar over the last 20 bars. It breaks above resistance on a bar that trades 540,000 shares, a ratio of 1.8. The same price move on 210,000 shares, a ratio of 0.7, would be weaker evidence.
Common mistakes
- Comparing raw volume across symbols. Normalize against each instrument's own average.
- Reading a partial bar as complete. A bar that is still forming has only part of its eventual volume.
- Ignoring the time of day. Stock volume clusters near the open and close, so a midday bar looks quiet by comparison.
How PatternX uses it
Every PatternX signal must pass one volume rule: the breakout bar's volume must reach 1.2× the 20-bar average. No detector adds a pattern-specific volume rule beyond that, and because the breakout bar may still be forming, the check uses the volume traded so far. In the PatternX Score, the surge against the 20-bar average carries 11% of the weight. For crypto, a symbol also needs at least $3M of 24-hour volume; markets traded through brokers are exempt. PatternX AI's volume-quality factor makes its own comparison of the last bar with the 20-bar average.