EquiVolume

What is EquiVolume?

EquiVolume is a charting style introduced by Richard W. Arms Jr. in his 1971 book Profits in Volume. Each period is drawn as a box whose height spans the high-to-low range and whose width is proportional to the period's volume, so heavy-participation bars print wide, quiet bars print narrow, and the separate volume pane is folded into the price plot itself. The CandleVolume variant keeps candlestick open-close bodies while borrowing the volume-scaled width.

Reading the chart is an exercise in effort vs result. A tall, wide box (Arms called it a power box) is range with participation, the signature of a move with real backing. A tall, narrow box is movement on thin trade, easier to unwind. A short, wide box is heavy volume that went nowhere, which near the edge of a move often reads as absorption and precedes some turns, though not reliably enough to trade on its own. Widths are relative to recent bars, so the same volume prints differently in different eras of the chart.

How traders use it

• To qualify breakouts: a breakout printing wide boxes shows participation behind the move, while narrow boxes flag a thin push that convention reads as more failure-prone, the box-width version of checking volume at breakout.
• To spot climactic turns: short, wide boxes after an extended run mark heavy two-sided trade with little progress, a classic exhaustion candidate that still needs price confirmation before acting.
• To watch consolidations mature: boxes that narrow as a range develops show volume drying up, useful context for judging whether a resolution attempt has fuel behind it.