This calculator finds the density of a substance from its mass and volume. Density determines whether an object floats or sinks: anything less dense than water floats on it.
What the symbols mean
- ρ (rho) — density (kilograms per cubic metre).
- m — mass (kilograms).
- V — volume (cubic metres).
Worked example
A block with a mass of 600 g and a volume of 200 cm³ has a density of 600 / 200 = 3 g/cm³ — three times denser than water, so it sinks.
Want the full story? Read our guide: Density and Pressure.
How the formula works
Density measures how much mass is packed into a given volume. Two objects of the same size can have very different densities depending on what they are made of. Comparing a material's density to that of water (1,000 kg/m³) tells you immediately whether it will float or sink.
Common mistakes to avoid
- Mixing units. Keep mass and volume consistent — grams with cm³, or kilograms with m³.
- Confusing density with weight. A small dense object can weigh less than a large light one.
Where it is used
Density explains buoyancy and flotation, identifies materials, and is central to fluid mechanics, geology and engineering.