About the Density Calculator
Density tells you how much mass is packed into a given volume. It is mass divided by volume, so a litre of water at about 1,000 kg per cubic metre is far lighter than a litre of lead. This density calculator can find any one of density, mass or volume when you give the other two, in whichever units you have: kilograms, grams, pounds, ounces or tonnes; litres, millilitres, cubic metres, cubic centimetres, cubic feet, cubic inches or US gallons. It reports density in several units, names the closest everyday material and tells you whether the object would float in fresh water.
Updated October 2026
How to use the Density Calculator
- 1Choose whether you want density, mass or volume.
- 2Enter the two values you know and select their units.
- 3If you know the density, type it in kg/m³ (1 g/cm³ equals 1,000 kg/m³).
- 4Read the answer and its conversions to other units.
- 5Check the closest material and the float or sink hint.
Typical densities to compare against
- Air at room temperature: about 1.2 kg/m³
- Cork: about 240 kg/m³; oak wood: about 750 kg/m³
- Ice: about 917 kg/m³; fresh water: 1,000 kg/m³
- Concrete: about 2,400 kg/m³; aluminium: about 2,700 kg/m³
- Steel: about 7,850 kg/m³; copper: about 8,960 kg/m³
- Lead: about 11,340 kg/m³; gold: about 19,320 kg/m³
Using density in practice
Builders use density to estimate how heavy a concrete slab or steel beam will be before ordering. Cooks compare the density of ingredients when converting between cups and grams. Jewellers check metals by weighing them and measuring displaced water. Shippers need density to work out whether a package will be charged by weight or by volume.
Avoiding common mistakes
The most common error is mixing units, such as grams with cubic metres, which is why the calculator converts everything to SI units first. Another is forgetting that a volume given in millilitres is not the same as cubic metres: 1 litre is 0.001 cubic metres. For related work see the Volume Calculator, the Unit Converter, the Concrete Calculator for slab weights and the Gravel Calculator for loose materials.
Features
- Solve for density, mass or volume
- Six mass units and seven volume units
- Density in kg/m³, g/cm³, lb/ft³ and lb per gallon
- Closest common material from a built-in list
- Float or sink hint for fresh water
- Clear errors for zero or negative inputs
- Runs in your browser
Frequently asked questions
What is the density formula?
Density equals mass divided by volume. A 500 gram block with a volume of 250 cubic centimetres has a density of 2 grams per cubic centimetre, or 2,000 kg per cubic metre. Rearranged, mass equals density times volume, and volume equals mass divided by density.
What are the units of density?
In the metric system density is kilograms per cubic metre, though grams per cubic centimetre is common for solids and liquids. Pure water is about 1 g/cm³ or 1,000 kg/m³. In the US, pounds per cubic foot is often used, and water is about 62.4 lb/ft³.
How do I know if something will float?
An object floats in a fluid when its average density is lower than the fluid's. Fresh water is about 1,000 kg/m³ and sea water about 1,025 kg/m³. Wood at 750 kg/m³ floats, while steel at 7,850 kg/m³ sinks. Ships float because their hollow shape lowers their average density.
How do I find the density of an irregular object?
Weigh it to get the mass, then find its volume by lowering it into a measuring container of water and noting how much the level rises. Divide the mass by that volume. Make sure the object does not absorb water or float, or the volume will be wrong.
Does temperature change density?
Yes. Most materials expand when heated, so the same mass takes up more volume and the density drops. Water is unusual: it is densest at about 4 degrees Celsius. The values here are typical room-temperature figures and are rounded.
How do I convert g/cm³ to kg/m³?
Multiply by 1,000. A density of 7.85 g/cm³, which is steel, is 7,850 kg/m³. To go the other way, divide by 1,000. The result table shows both so you do not have to convert.