About this calculator
The relative density tells you whether the material floats or sinks in water.
How to use it
- Choose what to find, enter the other values with their units, and read the answer in every common unit.
The formula
ρ = m ÷ V
- ρ
- density
- m
- mass
- V
- volume
Worked example
500 g of metal with a volume of 185 cm³
- ρ = 500 ÷ 185 = 2.70 g/cm³ = 2,700 kg/m³.
- That matches aluminium; specific gravity 2.70, so it sinks.
What the result means
Water is about 1 g/cm³ (1,000 kg/m³). Anything less dense floats.
Assumptions
- Uniform material.
Limitations
- Density of liquids and gases changes with temperature.
Frequently asked questions
What is the density of water?
About 1,000 kg/m³, or 1 g/mL.
What is specific gravity?
Density divided by the density of water.
How do I find the volume of an odd shape?
Measure the water it displaces.
Last reviewed on 6 October 2026. Found a mistake? Tell us.