Supported units
- Kilogram per cubic meter (kg/m³)
- Gram per cubic centimeter (g/cm³)
- Pound per cubic foot (lb/ft³)
- Pound per cubic inch (lb/in³)
Conversion tool
Density Converter
Select a category, enter a value, and convert between compatible units.
Density units explained
Density is mass divided by volume. Kilograms per cubic metre is the SI unit, while grams per cubic centimetre and pounds per cubic foot are also widely used.
Common engineering uses
Density conversion is useful for material selection, fluid calculations, buoyancy and mass-to-volume estimates. Density may change with temperature and pressure.
Formula
ρ = m / V
Density equals mass divided by volume. The SI unit is kilograms per cubic metre. Because the volume unit is cubed, density conversion factors must account for the cube of the corresponding length conversion.
- ρ = density, measured in kilograms per cubic metre (kg/m³)
- m = mass, measured in kilograms (kg)
- V = volume, measured in cubic metres (m³)
Common conversions
| From | Equivalent value |
|---|---|
| 1 gram per cubic centimetre (g/cm³) | 1,000 kilograms per cubic metre (kg/m³) |
| 1 kilogram per litre (kg/L) | 1,000 kilograms per cubic metre (kg/m³) |
| 1 kilogram per cubic metre (kg/m³) | 0.001 gram per cubic centimetre (g/cm³) |
| 1 pound per cubic foot (lb/ft³) | approximately 16.0185 kg/m³ |
| 1 kilogram per cubic metre (kg/m³) | approximately 0.062428 lb/ft³ |
| 1 pound per cubic inch (lb/in³) | approximately 27,679.9 kg/m³ |
Convert 7.85 g/cm³ to kg/m³
- Use the relationship 1 g/cm³ = 1,000 kg/m³.
- Multiply 7.85 by 1,000.
- 7.85 × 1,000 = 7,850 kg/m³.
7.85 g/cm³ = 7,850 kg/m³
A value near 7.85 g/cm³ is typical of many steels, but an exact material value depends on composition and temperature.
Engineering applications
- Estimating component mass from material density and volume.
- Selecting and identifying engineering materials.
- Calculating buoyancy, hydrostatic forces and fluid-system behaviour.
- Converting between volumetric flow and mass flow when the fluid density is known.
- Planning storage, transport and process quantities for liquids, powders and bulk materials.
Common mistakes
- Converting only the mass unit and forgetting that the length unit in the denominator is cubed.
- Confusing mass density with weight density or specific weight.
- Using density at one temperature or pressure for a state where the material density is different.
- Treating specific gravity as if it included density units; specific gravity is dimensionless.
- Confusing true material density with bulk density, which includes spaces between particles.
Frequently asked questions
How many kg/m³ are in one g/cm³?
One gram per cubic centimetre equals exactly 1,000 kilograms per cubic metre.
Is density the same as specific gravity?
No. Density has units. Specific gravity is a dimensionless ratio comparing a substance's density with a reference density.
Does density change with temperature?
Usually yes. Thermal expansion changes volume, so density changes even when mass remains constant.
How can density be used to calculate mass?
Multiply density by volume, using consistent units: m = ρ × V.
What is the difference between density and bulk density?
Material density describes the substance itself. Bulk density includes voids between particles or pieces in the measured volume.