Volume Chart

A Volume Chart is a chart, it can be a bar or candle chart, where each bar is made up of price changes that occurred when a constant (fixed) number of contracts were traded.

A Volume Chart is also often referred to as a Constant Volume Chart.

On a Volume Chart, each time the specified number of contracts are traded, a new bar or candle is created from which the Open, High, Low, and Close prices are collected for that bar.

Here is a discussion of various chart types and each of their merits: Chart Types