Density is defined as mass per unit volume, so it is necessary to measure both the weight and volume of an object to determine its density. Use a scale to measure the object's weight. A ruler can be used to measure the dimensions of an object and calculate its volume.

The volume of irregularly shaped solids can be found by using the displacement method, which the object is placed in a graduated cylinder containing a known volume of water. The subsequent change in water level is equal to the volume the object displaces. When calculating the density of a liquid, a graduated cylinder can be used to measure the liquid's volume.