Volume is a three-dimensional extension of the two-dimensional measurement of area. The area of a circle is determined by the formula pi x radius squared (?r2). Giving height to a circle creates a cylinder, and the formula for the volume of the cylinder adapts by multiplying the area of the circle with the height of the cylinder. This gives a formula for the volume of a right circular cylinder as pi times the radius squared times the height (? x r2 x h).

Measure the radius of the cylinder. The radius is half the diameter or the distance from the center of the cylinder to the side.

Measure the height of the cylinder. Use the same units of measurement used to measure the radius.

Calculate the volume according to the formula pi times the radius squared times the height (v = ? x r2 x h). For example, a cylinder with a radius of three centimeters and a height of five centimeters would have a volume of 141 cubic centimeters (? x 3 cm x 3 cm x 5 cm = 141 cm3).