Density calculator
Density, mass or volume from the other two, in metric or US units.
About this calculator
This density calculator finds the density of an object or material from its mass and volume, or the mass or volume from the density.
Mix any units, from grams and cubic centimetres to pounds and gallons, and see whether it would float or sink in water.
How it works
Density is mass ÷ volume, ρ = m ÷ V. Rearranged, mass = density × volume and volume = mass ÷ density. Values are converted through kilograms and cubic metres, so you can mix any units.
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Worked example
- Find: Density
- Mass: 500
- Mass unit: g
- Volume: 250
- Volume unit: cm³ (mL)
- Density unit: kg/m³
Density: 2,000 kg/m³ (denser than water, so it sinks)
Common questions
What is the density of water?
About 1,000 kg/m³, or 1 g/cm³, at 4 °C. It is a little lower when warmer: about 997 kg/m³ at 25 °C.
How do I find density?
Divide the mass by the volume. A 500 g object with a volume of 250 cm³ has a density of 2 g/cm³.
Why do some things float?
Objects less dense than the liquid they are in float. Ice floats because, at 917 kg/m³, it is less dense than water.
Sources and further reading
The story behind it
Where the idea came from: Archimedes is said to have checked whether a king's crown was pure gold by measuring the water it displaced, comparing its density with that of gold.
The story, told by the Roman writer Vitruvius, has him shouting eureka in the bath. Whether or not it happened, measuring volume by displacement is still a standard way to find the density of odd shapes.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, so please double-check anything important.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
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