Calculate the total force of buoyancy acting on an object. Enter the density of the fluid and the volume of the displaced fluid to calculate the buoyancy force.

Buoyancy Formula

The following formula can be used to calculate a force due to buoyancy:

B = ρ * V * g

  • Where B is the buoyant force
  • ρ is the density of the fluid
  • V is the volume of the displaced fluid
  • and g is the acceleration due to gravity

Buoyancy Definition

Buoyancy is the force acting on an object in a fluid that prevents it from moving through the liquid or sinking. Typically the movement it’s resisting is sinking due to the gravity of the earth. Buoyancy is directly proportional to the density of the fluid and the volume of displaced fluid as you can tell through the equation presented above. Buoyancy is evident mostly in bodies of water, but can also be seen in the air when objects like balloons float upwards away from the earth. This is due to the buoyant force.

How to calculate buoyancy

The following example will go over a real-world example of how to calculate the buoyancy force on an object.

  1. The first step to calculating this force is to choose a gravitational acceleration you wish the force to oppose Most of the time you are observing a force on earth, so the gravitational constant would be 9.8 m/s^2. If the
  2. Next, choose a liquid and determine the density of the fluid either empirically or mathematically.
  3. Finally, place the object in the water and observe the total displaced water.

Enter all of the values into the equation or calculator above, and you have your buoyant force.


What is buoyancy?

Buoyancy is a phenomenon that occurs between substance of different densities. It is a force that prevents an object from moving through a liquid when combined with gravity.