Buoyancy Calculator

Archimedes' principle states that the upward buoyant force on an object equals the weight of the fluid it displaces. In formula form: F_b = rho_fluid x V_displaced x g, where rho_fluid is the fluid density in kg/m^3, V_displaced is the displaced volume in m^3, and g is gravity in m/s^2.

Compare the average density of the object (mass / volume) to the density of the fluid. If the object is less dense than the fluid it floats; if it is denser it sinks. A 1 kg block that takes up 1.5 L has an average density of 667 kg/m^3, which is lower than fresh water at 1000 kg/m^3, so it floats.

About 90 percent. Ice has a density near 917 kg/m^3 and sea water sits around 1025 kg/m^3. The submerged fraction equals rho_ice / rho_sea_water = 917 / 1025, which is about 0.895, so roughly 89.5 percent of an iceberg's volume sits below the surface.

Yes. Iron has a density of about 7874 kg/m^3, while mercury is 13534 kg/m^3. Because iron is the lighter material, an iron block floats in mercury with about 7874 / 13534 = 58.2 percent of its volume submerged.

A floating object only sinks until the displaced fluid weighs the same as the object. At that point the buoyant force equals the object's weight in air, not the larger force you would get if the object were fully submerged. The calculator reports both numbers: buoyant force is the equilibrium value, and net force shows how much push or pull the object would feel if fully submerged.