Buoyancy Calculator — Archimedes Principle
Apply Archimedes' principle to find the upward buoyant force on any object submerged in a fluid. Enter the submerged volume, pick a fluid (or type a custom density), and get the buoyant force and displaced-fluid mass instantly.
Fluid
m³
m/s²
Upward force exerted by the fluid on the submerged volume
- 1
Displaced fluid mass
1,000 kg/m³ × 0.001 m³ = 1Mass of fluid displaced equals fluid density times the submerged volume (Archimedes). - 2
Buoyant force
1 kg × 9.81 m/s² = 9.810
How does this calculator work?
Buoyant force equals fluid density times submerged volume times gravitational acceleration (F_b = ρ × V × g). A 1 litre object fully submerged in fresh water (1000 kg/m³) experiences an upward force of about 9.81 N — the weight of 1 kg of water.
Formula
How this is calculated
Archimedes' principle states that any object submerged in a fluid experiences an upward buoyant force equal to the weight of the fluid it displaces. The formula is F_b = ρ × V × g, where ρ is the fluid's density in kg/m³, V is the volume of the object that is below the fluid surface in m³, and g is gravitational acceleration (9.81 m/s² on Earth). The result is the force in newtons.
An object floats when the buoyant force equals or exceeds its own weight; it sinks when its weight is greater. This calculator computes only the buoyant force — to determine whether the object floats, also calculate the object's weight (mass × g) and compare the two.
The fluid densities in the dropdown are standard reference values at around 20 °C. In practice, density varies with temperature and pressure, so the result is an estimate for real fluids at non-standard conditions.
Frequently asked questions
Archimedes' principle states that the upward buoyant force on an object equals the weight of the fluid it displaces. In formula form: F_b = ρ_fluid × V_submerged × g, where ρ is the fluid density, V is the submerged volume, and g is gravitational acceleration.
No — buoyant force depends only on the volume of fluid displaced, not on the shape of the object. A 1 L cube and a 1 L sphere submerged in the same fluid experience exactly the same buoyant force.
Compare the buoyant force (this calculator) with the object's weight (mass × g). If buoyant force ≥ weight, the object floats; if buoyant force < weight, it sinks. Equivalently, compare densities: an object floats if its average density is less than the fluid's density.
Also known as
TG we-Calculate Editorial Team. (2026). Buoyancy Calculator — Archimedes Principle [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/buoyancy-calculator
TG we-Calculate Editorial Team. "Buoyancy Calculator — Archimedes Principle." TG we-Calculate. 2026. https://we-calculate.com/calculator/buoyancy-calculator.
TG we-Calculate Editorial Team, "Buoyancy Calculator — Archimedes Principle," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/buoyancy-calculator
@misc{wecalculate_buoyancy_calculator, title = {Buoyancy Calculator — Archimedes Principle}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/buoyancy-calculator}}, year = {2026}, note = {TG we-Calculate} }
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