Density Converter
Density measures how much mass is packed into a given volume, a fundamental property in physics, chemistry, materials science, and engineering. The SI unit is kilogram per cubic metre (kg/m³), but scientists often use gram per cubic centimetre (g/cm³) for convenience, especially in chemistry. Water at 4 degrees Celsius has a density of 1,000 kg/m³ or 1 g/cm³, serving as a reference point. Denser materials like lead have densities around 11,340 kg/m³, while less dense materials like foam might be 30 kg/m³. The imperial system uses pounds per cubic foot (lb/ft³) and pounds per cubic inch (lb/in³), common in the United States for engineering and materials specifications. Smaller quantities use ounces per cubic inch or cubic foot. Converting between density units is essential when sourcing materials internationally, comparing specifications, calculating weight from volume, or verifying material properties. This calculator displays ten density units: metric units from gram per cubic metre to kilogram per litre, plus imperial units from pounds per cubic foot to ounces per cubic foot, for instant conversion with NIST precision.
NIST conversion factors
All conversions below use standard NIST-defined factors, with all units expressed relative to kg/m³.
| Unit | Symbol | kg/m³ |
|---|---|---|
| Kilogram per cubic metre | kg/m³ | 1 |
| Gram per cubic metre | g/m³ | 0.001 |
| Gram per cubic centimetre | g/cm³ | 1,000 |
| Gram per litre | g/L | 1 |
| Milligram per millilitre | mg/mL | 1 |
| Kilogram per litre | kg/L | 1,000 |
| Pound per cubic foot | lb/ft³ | 16.01846 |
| Pound per cubic inch | lb/in³ | 27,679.905 |
| Ounce per cubic inch | oz/in³ | 1,729.994 |
| Ounce per cubic foot | oz/ft³ | 1.00115 |
Density converter: frequently asked questions
What is density?
Density is mass divided by volume, measuring how much matter is packed into a given space. The SI unit is kg/m³. Water has a density of 1,000 kg/m³. Lead is much denser at 11,340 kg/m³, while foam is less dense at about 30 kg/m³.
Why are there multiple density units?
Different fields use different units for convenience. Scientists use kg/m³ or g/cm³. Engineers in the US use lb/ft³ or lb/in³. Converting ensures clarity when comparing material specifications.
What does g/cm³ mean?
g/cm³ (grams per cubic centimetre) equals kg/L and is numerically equal to g/mL. It is common in chemistry and materials science. 1 g/cm³ equals 1,000 kg/m³.
How precise are these conversions?
These use NIST-defined conversion factors based on exact unit definitions. All conversions are mathematically precise to two decimal places.
What practical use is density conversion?
Comparing material properties from international sources, verifying material specifications, calculating shipping weight from volume, or checking flotation and displacement calculations all require density conversions.
Official sources
- NIST Handbook 44: Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices.
- NIST Special Publication 330: The International System of Units.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.