Remove the "cubed" from the unit of volume to find the unit of the side length. For example, if the volume is in inches cubed, the side length would be measured in inches.
Calculate the cube root, also known as the third root, of the volume to find the side length. The cube root of a number equals the original when multiplied by itself three times. For this example, if the cube's volume equals 64 cubic inches, the cube root of 64 equals 4, because 4 times 4 times 4 equals 64, so the side length would be 4 inches.
Raise the volume to the 1/3 power as an alternative way to calculate the side length from the volume. In this example, raise 64 cubic inches cubed to the 1/3 power to get 4 inches.