Density Converter
Convert between kg/m³, g/cm³, lb/ft³ and more.
Results update as you type.
How it works
A density converter restates how much mass sits in a given volume in a different unit, moving between kilograms per cubic metre and grams per cubic centimetre on the metric side, the closely related grams per millilitre, and pounds per cubic foot and per cubic inch on the customary side. It reduces your figure to kilograms per cubic metre, the SI unit for density, then scales out to the unit you choose, so one mechanism covers material data sheets, fluid properties, shipping weights and laboratory work alike. This matters because density is quoted in several coexisting units and the numbers look wildly different for the same substance. A materials table might list steel as 7.85 g/cm³, a shipping estimate as 490 lb/ft³ and an engineering model as 7,850 kg/m³ — all identical densities in different clothing. Comparing a plastic's data sheet against a metal's, or checking whether a material will float, is only possible once every value shares one unit. The convert-through-kilograms-per-cubic-metre method is used because every density unit has a fixed ratio to that base — one gram per cubic centimetre is exactly 1,000 kg/m³, one pound per cubic foot is about 16.02 kg/m³ — so pivoting through it keeps results exact and needs only one factor per unit. Note that grams per millilitre equals grams per cubic centimetre exactly, since a millilitre is a cubic centimetre. Engineers, chemists, machinists, shippers and students all rely on a density converter whenever a value lands in an unfamiliar unit.
Convert to kilograms per cubic metre via known factors, then to the target unit
The input is multiplied by its unit's fixed number of kilograms per cubic metre to express the density in that base, then divided by the target unit's value to complete the conversion. Because density is mass divided by volume, and both mass and volume units reduce to constants against the kilogram and the cubic metre, every density unit has a fixed ratio to the SI base, so chaining through it stays exact for all unit pairs with one stored factor each.
Source:International System of Units (SI) — NIST
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter value, from and to.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Converted density updates instantly as you type — no button to press.
Frequently asked questions
How do I convert g/cm³ to kg/m³?
Multiply the grams-per-cubic-centimetre figure by 1,000, since a gram is a thousandth of a kilogram but a cubic centimetre is a millionth of a cubic metre, giving a net factor of one thousand. So water at 1 g/cm³ is 1,000 kg/m³. To reverse it, divide by 1,000. This clean factor of a thousand makes the two units easy to switch between mentally.
Is g/mL the same as g/cm³?
Yes, exactly. One millilitre is defined as one cubic centimetre, so grams per millilitre and grams per cubic centimetre are numerically identical for any substance. Chemists often write g/mL for liquids and g/cm³ for solids, but the values are interchangeable. This converter treats them as equal, so converting between them always returns the same number you entered.
What is the density of water?
Pure water at about 4°C has a density very close to 1 gram per cubic centimetre, which equals 1,000 kilograms per cubic metre or about 62.4 pounds per cubic foot. This tidy value is why water is the reference for specific gravity: a material with density above 1 g/cm³ sinks in water, while one below it floats. Density changes slightly with temperature and dissolved substances.
How do I convert lb/ft³ to kg/m³?
Multiply the pounds-per-cubic-foot figure by about 16.02 to get kilograms per cubic metre. So a material at 50 lb/ft³ is about 801 kg/m³. To reverse it, divide by 16.02. The factor combines the pound-to-kilogram and cubic-foot-to-cubic-metre conversions, and the converter carries the full precision so the displayed answer is accurate to the decimals shown.
Why convert density through kg/m³?
The kilogram per cubic metre is the SI unit for density, so every other density unit has a fixed, exactly defined ratio to it. Using it as the pivot means the converter needs only one factor per unit rather than a separate rule for each pair, keeps results exact, and matches the unit that engineering and fluid-dynamics equations expect, which makes cross-checking calculations straightforward.