Enter the initial water level, final water level, and mass of the object into the calculator to determine the density of the object.

Water Displacement Formula

The following formula is used to calculate density from water displacement.

D = m / (FW - IW) 
  • Where D is the density g/cm^3
  • m is the mass in grams
  • FW is the final water level (mL)
  • IW is the initial water level (mL)

Water Displacement Definition

Water displacement is defined as the density of an object calculated through the displacement of a certain amount of water.

Water Displacement Example Problem

How to calculate water displacement?

The following example explores how to calculate the density of an object using the water displacement method. In this case, an irregularly shaped object is placed in a container of water and the displacement is measured.

First, determine the mass of the object in grams.

For this example problem, the mass of the object is measured to be 500 grams.

Next, measure the initial water level before the object is placed into the container.

In this case, the water level is at 400 mL prior to anything being added to the water.

Next, place the object into the water and record the final water level.

For this example, the final water level is measured to be 500 mL.

Finally, calculate the density using the formula above:

D = m / (FW – IW)

D = 500 / (500 – 400)

D = 5 g/cm^3

Even though the water displacement is measured in mL, these units are equivalent to centimeters cubed, so the final result can be expressed in grams per cm^3 or mL.


What is the water displacement method?

The water displacement method is a method for calculating the density and volume of an object. It does this through measure the amount of displaced water when the object is submerged under water that is in a container. The amount of displaced water is equal to the volume. This volume can then be used to calculate the density.