Core terms
Dollar volume
Shares traded multiplied by their price over a period: how much money changed hands. It compares trading activity across stocks at different prices better than share volume does.
Share volume is easy to misread. Thirty million shares at $0.40 is $12 million of trading; three million shares at $12.00 is $36 million (Illustrative). An exact figure sums price × shares over every trade; a common shortcut multiplies the day's share volume by the closing price.
For context, that shortcut applied to 671 gap-ups of 20% or more gave a median full-day dollar volume of about $110 million, and one in ten traded less than about $20 million (n = 671; 2026-07-01 to 2026-10-02; FennEdge archive; as of 2026-10-02).
A full-day figure is known only after the close and says little about the minute you trade: much of a gapper's volume can come in premarket or the first half hour.
What traders should verify
Compare dollar volume so far, at the time of the decision, with your intended position value, and record it together with the spread and displayed depth. Use full-day figures as review context, not as entry conditions.
Do not conflate
Trader usage; there is no official definition. Dollar volume is a total over a period; it does not show the spread or the depth at the moment of an order, and a high daily figure can hide thin minutes.
Primary source
Trader usage: there is no official definition, and platforms and tools may calculate it differently.