Calculators
Buoyancy Calculator
Find the buoyant force, fluid density, or displaced volume with F = ρ × V × g, plus the equivalent supported mass, locally in your browser.
Buoyancy is the upward force a fluid exerts on a submerged or floating object. It equals the weight of the fluid the object displaces. Choose what to solve for, then enter the other values using SI units: density in kilograms per cubic metre (kg/m³), volume in cubic metres (m³), and force in newtons (N). The result also reports the equivalent supported mass and the displaced volume in litres. Calculations run locally in your browser; your values are not uploaded or stored.
Solve F = ρ × V × g for the buoyant force, density, or displaced volume.
Buoyancy is the upward force a fluid exerts on a submerged or floating object, and it equals the weight of the fluid the object displaces (Archimedes’ principle). Choose what to solve for, then enter the other values using SI units: fluid density in kilograms per cubic metre (kg/m³), displaced volume in cubic metres (m³), and force in newtons (N). For example, fresh water at 1000 kg/m³ displacing 0.5 m³ gives a buoyant force of 1000 × 0.5 × 9.81 = 4905 N, the same as the weight of about 500 kg. To solve for density enter the force and volume, and to solve for volume enter the force and density. The result also reports the equivalent supported mass in kilograms and pounds and the displaced volume in litres. This is a physics estimate that assumes standard gravity of 9.81 m/s² and a constant fluid density; all calculations stay in your browser.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
Which formula does the buoyancy calculator use?
It uses Archimedes’ principle: the upward buoyant force equals the weight of the fluid displaced, F = ρ x V x g, where ρ is the fluid density in kg/m³, V is the displaced volume in m³, and g is standard gravity, 9.81 m/s². Rearranged, ρ = F / (V x g) and V = F / (ρ x g). For example, fresh water at 1000 kg/m³ displacing 0.5 m³ gives F = 1000 x 0.5 x 9.81 = 4905 N.
What does the equivalent supported mass mean?
It is the mass whose weight equals the buoyant force, found by dividing F by g. A buoyant force of 4905 N supports about 500 kg in Earth’s gravity. A floating object displaces enough fluid that this force equals the object’s weight, and a fully submerged object experiences the buoyant force for its entire volume.
Which units should I use?
Use SI units: fluid density in kilograms per cubic metre (kg/m³), displaced volume in cubic metres (m³), and force in newtons (N). The result also reports volume in litres, where 1 m³ = 1000 L, and the equivalent mass in kilograms and pounds. Any consistent set of units works, as long as the formula’s units match.
Which inputs are accepted?
Enter positive values up to 1,000,000,000,000. Densities below about 1 kg/m³ or above about 25,000 kg/m³ are physically unusual, so double-check a surprising figure. Missing, non-numeric, or out-of-range entries show a clear message instead of a misleading number, and a result that is too large to display is rejected rather than shown imprecisely.
Is this accurate enough for engineering or diving?
It is an ideal physics estimate. It assumes a constant fluid density and standard gravity of 9.81 m/s², and it ignores temperature, salinity, depth, object shape, and the fluid’s motion. Real ocean, freshwater, and process fluids vary with conditions, so verify critical work with measured data. The calculation and copy run locally in your browser; CodeASystem does not upload or store your values.