Sphere Density Calculator

The sphere density calculator needs either radius or volume and mass of a sphere to calculate the density for you. It can also do the maths all the way around.

Density7,849.5218 kg/m³7.849522 g/cm³, 490.0299 lb/ft³

Volume0.523599 litres0.000523599 m³ — from ⁴⁄₃πr³

Mass4.11 kg

Density7,849.5218 kg/m³7.849522 g/cm³ — numerically the same as the specific gravity of a solid or liquid

Specific gravity7.86368relative to water at 20 °C — it sinks in water

Specific volume0.0001274 m³/kgthe reciprocal of density

Weight on Earth40.3053 Ndensity is about mass, not weight — the same object has the same density on the Moon

Against balsa wood49.0595×160 kg/m³

Against water7.8637×998 kg/m³

Against concrete3.2706×2,400 kg/m³

Against aluminium2.9072×2,700 kg/m³

Against steel0.9999×7,850 kg/m³

Against lead0.6922×11,340 kg/m³

Against gold0.4067×19,300 kg/m³

The formula

ρ = m ÷ V

Density is intensive, weight is not

Density is mass per unit volume, and it is an intensive property: cutting an object in half leaves the density unchanged, because both mass and volume halve. That is what makes it useful for identifying a material regardless of how much of it you have.

It is also independent of gravity. An object taken to the Moon weighs a sixth as much but has exactly the same density, because neither its mass nor its volume changed. Confusing density with "heaviness" is the usual source of trouble here.

Specific gravity is density relative to water, so for solids and liquids it is numerically the same as density in g/cm³ — a happy coincidence of water being almost exactly 1 g/cm³. Anything above 1 sinks in water and anything below floats, with the submerged fraction equal to the ratio itself.

Note that density varies with temperature, and for gases with pressure too. Water is unusual in reaching maximum density at 4 °C rather than at its freezing point, which is why ice floats and why lakes freeze from the top down.