Buoyant Force CalculatorFree online other calculator — instant results, no sign-up
Calculate buoyancy from displaced fluid volume and density.
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About the Buoyant Force Calculator
The Buoyant Force Calculator finds the upward force exerted by a fluid using its density and the volume displaced by an object. It applies Archimedes’ principle with standard gravitational acceleration to report buoyancy in newtons. With the default displaced volume of 0.01 m³ and fluid density of 1000 kg/m³, the result is 98.0665 N.
- Displaced volume (m³)
- The volume of fluid displaced by the submerged portion of the object, measured in cubic meters (m³), defaults to 0.01.
- Fluid density (kg/m³)
- The mass per unit volume of the surrounding fluid, measured in kilograms per cubic meter (kg/m³), defaults to 1000.
Formula and method
F_b = ρ × V_d × g = 1000 × 0.01 × 9.80665 = 98.0665 N
- F_bBuoyant force acting upward on the object, in newtons (N).
- ρDensity of the displaced fluid, in kilograms per cubic meter (kg/m³).
- V_dVolume of displaced fluid, in cubic meters (m³).
- gStandard gravitational acceleration, fixed at 9.80665 m/s².
Multiply fluid density by displaced volume to obtain the mass of displaced fluid, then multiply by standard gravitational acceleration to obtain its weight. By Archimedes’ principle, this weight equals the buoyant force. For the default inputs, 1000 kg/m³ × 0.01 m³ gives 10 kg of displaced fluid, and 10 kg × 9.80665 m/s² gives 98.0665 N.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Displaced volume0.01 m³
- Fluid density1000 kg/m³
Results
- Result98.0665 N
How to use the Buoyant Force Calculator
- 1Determine the volume of fluid displaced; for a partially submerged object, use only its submerged volume.
- 2Enter the displaced volume in m³, or retain the default of 0.01.
- 3Enter the fluid density in kg/m³, or retain the default of 1000.
- 4Calculate the buoyant force using F_b = ρ × V_d × 9.80665.
- 5Read the result in newtons; the default inputs produce 98.0665 N of upward buoyant force.
Reading your result
The Result row shows the magnitude of the upward buoyant force in newtons (N). A result of 98.0665 N means the displaced fluid provides that much upward force on the object. This is not the net force: compare it with the object's weight and any other forces to assess motion or equilibrium.
Limitations
The calculation assumes a fluid at rest with uniform density and uses fixed standard gravity of 9.80665 m/s² rather than local gravity. Use nonnegative displaced volume and positive fluid density, with units converted before entry. Density can vary with temperature, pressure, and composition. This tool does not account for drag, flow-induced lift, surface tension, or changes in density with depth, and it does not determine whether an object will float without information about its weight and available displacement. Displayed decimal places do not imply that the inputs are equally precise.
Common questions
Should I enter the object's total volume or only its submerged volume?+
Enter the volume of fluid actually displaced. For a fully submerged solid object, this generally equals its total volume; for a partially submerged object, use only the portion below the fluid surface. For hollow objects, account for whether fluid can enter the cavity.
Why do the default inputs give 98.0665 N?+
The displaced fluid has a mass of 1000 kg/m³ × 0.01 m³ = 10 kg. Multiplying by the calculator's fixed gravity of 9.80665 m/s² gives a buoyant force of 98.0665 N.
Can I use this buoyancy calculator for fluids other than water?+
Yes. Enter the density of the liquid or gas at the relevant conditions and the volume displaced. The default density of 1000 kg/m³ is an approximation for water, not a universal fluid density.
Does the buoyant force tell me whether an object will float?+
Not by itself. For free-floating equilibrium with no other vertical forces, buoyant force must equal the object's weight. If the object's weight exceeds the maximum buoyant force available when fully submerged, it cannot float unsupported.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.