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Archimedes' Principle Calculator.

Calculate buoyant force from displaced fluid volume and density.

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buoyantForce: 98.0665

buoyantForce

98.066500

Use Cases

Determine if an object floats or sinks

Compare the buoyant force to the object's weight. If buoyant force is greater, the object floats; if less, it sinks.

Example: A 0.5 m³ object in water (density 1000 kg/m³) with g=9.81 m/s² has a buoyant force of 4905 N.

Design floating structures

Engineers use buoyant force calculations to ensure boats, buoys, and other floating structures have sufficient displacement to stay afloat.

Example: Calculate the buoyant force on a pontoon with a displaced volume of 2 m³ in seawater (density 1025 kg/m³).

Frequently Asked Questions

What is Archimedes' principle?
Archimedes' principle states that the buoyant force on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. This calculator uses that principle to compute the buoyant force.
How is buoyant force calculated?
Buoyant force is calculated by multiplying the fluid density (kg/m³), the displaced volume (m³), and the gravitational acceleration (m/s²). The formula is F_b = ρ * V * g.
What units should I use?
Enter fluid density in kilograms per cubic meter (kg/m³), displaced volume in cubic meters (m³), and gravitational acceleration in meters per second squared (m/s²). The result will be in newtons (N).

Tips & Common Mistakes

Tips

  • Use the standard gravitational acceleration of 9.81 m/s² for Earth, but adjust if you're working on another planet or in a different context.
  • Ensure the displaced volume is the volume of fluid actually displaced, not the total volume of the object if it is not fully submerged.
  • For accurate results, use the density of the fluid at the actual temperature and pressure, as density can vary.
  • Remember that the buoyant force acts upward, opposing the weight of the object.

Common Mistakes to Avoid

  • Using the object's total volume instead of the displaced volume when the object is only partially submerged.
  • Forgetting to convert units to the required ones (kg/m³, m³, m/s²) before entering values.
  • Confusing fluid density with object density; the buoyant force depends on the fluid's density, not the object's.

Last updated: August 13, 2026