Density Converter
Convert density between kg/m³, g/cm³, and lb/ft³.
Conversion sheet
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Density — mass packed into a given volume — shows up in metric form (kg/m³, g/cm³, g/mL) in science and in pounds per cubic foot or cubic inch in US engineering. This converter translates a density value between all five so material specs, datasheets, and calculations line up.
How it works
Every density value converts through kilograms per cubic meter as the base unit.
All units reference kilograms per cubic meter (kg/m³) as the base. The factors are: 1 g/cm³ = 1000 kg/m³, 1 g/mL = 1000 kg/m³, 1 lb/ft³ = 16.0185 kg/m³, and 1 lb/in³ = 27679.9 kg/m³. Because a cubic centimeter and a milliliter are the same volume, g/cm³ and g/mL are identical and both equal 1000 kg/m³.
A handy anchor: pure water at 4 °C is 1 g/cm³, which is exactly 1000 kg/m³ or about 62.4 lb/ft³. Comparing a material's density to water tells you instantly whether it will float (less than 1 g/cm³) or sink.
Result = input value × (kilograms-per-cubic-meter per source unit ÷ kilograms-per-cubic-meter per target unit). Each unit's kg/m³ factor is fixed, so converting is one multiplication by the ratio of the two factors.
Worked examples
Convert 1 g/cm³ to kg/m³. → 1000 kg/m³
Kilograms per cubic meter is the base unit, so 1 × 1000 = 1000 kg/m³ — the density of water and a useful reference point.
Convert 7.85 g/cm³ (carbon steel) to pounds per cubic foot. → ≈ 490.1 lb/ft³
First to base: 7.85 × 1000 = 7850 kg/m³. Then 7850 ÷ 16.0185 ≈ 490.1 lb/ft³.
Tips & gotchas
- Grams per cubic centimeter and grams per milliliter are numerically identical — 1 cm³ equals 1 mL — so you never need to convert between those two.
- Use water (1 g/cm³ = 1000 kg/m³) as a mental yardstick: anything denser sinks in water, anything lighter floats. It is a fast sanity check on any converted value.
- Density changes with temperature, especially for gases and liquids. Material datasheets usually quote density at a reference temperature — convert the units, but keep that reference condition in mind.
- Pounds per cubic inch produces very large kg/m³ numbers (factor 27679.9), so it is reserved for very dense materials. If a lb/in³ figure looks tiny, double-check it is not actually lb/ft³.
FAQ
Why are g/cm³ and g/mL the same in this converter?
Because one cubic centimeter is exactly one milliliter. Both units describe grams of mass in that same volume, so they share the identical factor of 1000 kg/m³.
What is the density of water in these units?
Pure water at 4 °C is 1 g/cm³, equal to 1000 kg/m³ or about 62.4 lb/ft³. It is the standard reference for whether a material floats or sinks.
How is density different from specific gravity?
Specific gravity is density divided by the density of water, so it is a unitless ratio. A material with density 7850 kg/m³ has a specific gravity of about 7.85. This tool reports density in real units, not the ratio.
Does temperature affect the conversion?
The unit conversion factors are fixed, but a material's actual density shifts with temperature. Make sure the density value you enter is quoted at the temperature relevant to your application.
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