The mass of a cube is calculated as its density times its volume. If the values for density and volume are not provided, they should be measured or calculated.
Volume can be calculated if one knows the length, width or height, as all three values are the same for a cube. Multiply these three values together to find the volume. Once the density and volume values are known, multiply them together. Because most scientific problems involve the metric system, volume is usually measured in cubic meters and mass is usually measured in kilograms, making density expressed as kilograms per cubic meter.