Buoyancy Calculator — Archimedes' Principle

Calculate the buoyant force on a submerged object and determine whether it floats or sinks.

Fluid Mechanics I

Common fluids — click to auto-fill density

Inputs

Submerged volume V (L)

Fluid density ρ (kg/m³)

Object density (optional — for float/sink analysis) ρ (kg/m³)

If provided, the calculator will determine whether the object floats, sinks, or is neutrally buoyant.

Theory

Archimedes' Principle:

F = ρ × V × g

Float / Sink condition:

Object density < fluid density → floats (submerged fraction = ρ_obj / ρ_fluid)
Object density = fluid density → neutrally buoyant
Object density > fluid density → sinks

The buoyant force equals the weight of the fluid displaced. It acts upward through the centre of buoyancy (centroid of the submerged volume) and opposes gravity.