About this tool
Buoyancy Force Calculator is a free, in-browser tool that applies Archimedes' principle to find the upward buoyant force on an object in a fluid. Pick a fluid preset (fresh water, seawater, oil or air) or type any density, enter the object's volume, and optionally its mass to get a float-or-sink verdict. Nothing is uploaded — every figure is computed locally as you type.
The buoyant force is Fb = ρ·V·g, where ρ is the fluid density, V is the submerged volume and g is gravitational acceleration (9.81 m/s²). This force equals the weight of the displaced fluid. When you supply the object's mass, the tool derives its density (mass ÷ volume): if that is less than the fluid's it floats, otherwise it sinks. Apparent weight is the true weight W = m·g minus the buoyant force.
For a floating object the fraction submerged equals the density ratio ρ_object ÷ ρ_fluid, so an object half the fluid's density floats with half its volume under the surface. Change any input to explore how denser fluids like seawater increase lift and reduce how deep a body sits.