Density Calculator
Density answers a question every material poses: how much stuff sits in a given space. It is why wood floats and why a litre of water weighs a kilogram. The number is mass divided by volume, but the answer shifts with units more than most people expect — kg/m³ for engineering, g/cm³ for chemistry, lb/ft³ for imperial tables — so this calculator takes any mix of mass and volume units and reports all three together.
Enter values
Results
- Density
- 1,000 kg/m³
- In grams per cubic centimetre
- 1 g/cm³
- In pounds per cubic foot
- 62.43 lb/ft³
How is the Density calculated?
Two number fields take the mass and the volume, each with its own unit menu: kilograms, grams, pounds or ounces for mass; cubic metres, litres, millilitres, cubic centimetres, cubic feet or US gallons for volume. Both are converted to kilogrammes and cubic metres, divided for the density in kg/m³, then rendered again as g/cm³ — divide by a thousand — and lb/ft³ — multiply by 0.0624279606.
Formula
ρ = m ÷ V, where ρ is the density, m the mass in kilograms and V the volume in cubic metres; the result is kg/m³. Dividing by 1,000 restates it as g/cm³, and multiplying by 0.0624279606 as lb/ft³. Converting units before the division matters: 1 L is 0.001 m³ exactly, and a US gallon is 3.785411784 L.
Example
One kilogram of water occupies one litre: V = 0.001 m³, so ρ = 1 ÷ 0.001 = 1,000 kg/m³ — the reference value every density table starts from. That is exactly 1 g/cm³, and 1,000 × 0.0624279606 ≈ 62.43 lb/ft³. The imperial pair agrees: 8.3454 lb of water fills one US gallon, converting to 3.7854098 kg over 0.003785411784 m³, a density of 999.9995 kg/m³ — water, within measurement error.
Things to remember
Density is a material's signature: compare against a reference table and the material often identifies itself — aluminium near 2,700 kg/m³, steel near 7,850, ice near 917. Convert units before dividing; a kilogram in a litre is the classic thousand. Pair this page with the volume converter for tank sizing.
Frequently Asked Questions
How do you calculate density from mass and volume?
Divide the mass by the volume, using matching units first. One kilogram in one litre — that is 0.001 m³ — gives 1 ÷ 0.001 = 1,000 kg/m³. The calculator performs every unit conversion for you, so mixed inputs like pounds and gallons still land correctly.
What units does this density calculator use?
It works in SI behind the scenes — kilograms over cubic metres — and then reports the same density in kg/m³, g/cm³ and lb/ft³. You may enter mass in kg, g, lb or oz and volume in m³, L, mL, cm³, ft³ or US gallons.
Why is water's density exactly 1,000 kg/m³?
By definition of the units: one litre of water was chosen long ago as weighing one kilogram, and a litre is one thousandth of a cubic metre. The real value sits a fraction below at room temperature, which is why the calculator's gallon check returns 999.9995 rather than an exact thousand.
What does a density below 1,000 kg/m³ tell you?
That the material floats on water — anything from cork near 500 kg/m³ to ice at about 917 kg/m³ qualifies. Above that value it sinks, like aluminium around 2,700 kg/m³ or steel near 7,850, which is why solid hulls still displace the water they cannot outrun.
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