Empuxo (Arquimedes)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
E = ρVg
About this calculator
The buoyancy calculator, based on Archimedes' principle, determines the buoyant force acting on an object submerged in a fluid. Buoyancy is the upward vertical force exerted by the fluid, equal to the weight of the fluid displaced by the object. This explains why objects float or seem lighter in water.
The calculation uses the formula E = ρVg, where E is buoyancy in newtons, ρ is fluid density (kg/m³), V is the displaced fluid volume (m³), and g is gravitational acceleration (9.81 m/s²). Simply enter fluid density (e.g., water 1000 kg/m³), displaced volume, and gravity (default 9.81) to get the buoyant force.
Use this calculator for naval engineering projects, boat design, object flotation, or to understand phenomena like an iceberg floating in the sea. It is also useful in physics labs for experiments with density and buoyancy.
Cautions: fluid density must be correct (fresh water ~1000 kg/m³, salt water ~1025 kg/m³). Displaced volume is the volume of the submerged part of the object, not its total volume if it floats. Gravity varies slightly with location, but 9.81 is suitable for most calculations.
Frequently asked questions
What is buoyancy?
Buoyancy is the upward force exerted by a fluid on a submerged object, equal to the weight of the displaced fluid.
Why do objects float?
An object floats if its weight is less than the buoyant force. Otherwise, it sinks.
How to calculate displaced volume?
If the object is fully submerged, displaced volume is its total volume. If it floats, it is the volume of the submerged part.
Does this calculator work for any fluid?
Yes, as long as you enter the correct fluid density (e.g., air ~1.2 kg/m³, mercury ~13546 kg/m³).
What is the unit of the result?
The result is given in newtons (N). To convert to kgf, divide by 9.81.