The Density Converter converts density units such as kilograms per cubic metre (kg/m³), grams per cubic centimetre (g/cm³), pounds per cubic foot, and pounds per gallon. Enter a density value in one unit and read the others with the factor and working shown.
Physics density solvers compute density from mass and volume. The Density Converter does not solve ρ = m/V. It only converts a density that is already known from one unit expression to another, using audited factors such as 1000 between kg/m³ and g/cm³.
Convert between units of density
The Density Converter routes each unit through an SI density in kilograms per cubic metre, then formats the target unit. Lab chemistry often uses g/cm³ or g/mL. Materials and fluids in SI engineering use kg/m³. US customary work may quote lb/ft³ or lb/gal.
Choose source and target units, enter the number, and results update live. Cascade mode lists several density labels at once so a handbook value in g/cm³ can be compared with a process sheet in kg/m³ without retyping.
Density is mass per volume. Changing only the unit must keep the physical density the same. If mass or volume still need calculating, use a mass or volume tool first, then convert the resulting density here.
Convert kg/m³ to g/cm³
One gram per cubic centimetre equals 1000 kilograms per cubic metre, because 1 g/cm³ = 1000 kg/m³ under metric prefix scaling of mass and length. Convert kg/m³ to g/cm³ by dividing by 1000. Convert g/cm³ to kg/m³ by multiplying by 1000.
g/cm³ = (kg/m³) ÷ 1000
kg/m³ = (g/cm³) × 1000Worked example: convert 7850 kg/m³ (approximate steel handbook density) to g/cm³.
1. Divide by 1000. 7850 ÷ 1000 = 7.85 g/cm³.
2. Reverse check. 7.85 × 1000 = 7850 kg/m³.
The Density Converter shows that divide-or-multiply step under the result. The same factor links kg/m³ to g/mL for liquids when 1 cm³ is taken as 1 mL, which is the usual identity for this conversion.
Convert to imperial density units
Pounds per cubic foot (lb/ft³) and pounds per gallon (lb/gal) appear on US material data sheets. The Density Converter converts them through SI using audited mass and volume factors rather than a memorized one-off constant for every pair.
A useful orientation figure: water near 1000 kg/m³ is about 62.4 lb/ft³ in common handbook rounding for freshwater at room-temperature reference conditions used in many US tables.
Exact converted values on the page come from the factor table, not from a mental 62.4 shortcut alone.
Pounds per US gallon describe density for fuels and chemicals sold by the gallon. Because a US gallon is a fixed volume, converting lb/gal to kg/m³ is still a pure unit change. Confirm whether a datasheet uses US gallons or imperial gallons before trusting a lb/gal figure; the Density Converter labels which gallon definition is active when both appear.
Use water as a density reference
Liquid water near 4 °C has a density of about 1000 kg/m³, which is 1 g/cm³. That round pair is why metric density feels intuitive: a substance at 0.8 g/cm³ is lighter than water; one at 7.85 g/cm³ is much denser. The Density Converter uses water as a mental reference, not as a temperature-dependent live model.
| Material (typical handbook) | kg/m³ | g/cm³ |
|---|---|---|
| Water (reference) | 1000 | 1 |
| Ethanol (approx.) | 789 | 0.789 |
| Aluminum (approx.) | 2700 | 2.7 |
| Steel (approx.) | 7850 | 7.85 |
Handbook densities vary with alloy, temperature, and porosity. The Density Converter changes units of whatever number you enter; it does not replace a material certificate. When a supplier lists density in g/cm³ and a model needs kg/m³, divide or multiply by 1000 as above and keep the source citation with the model.
Specific gravity is a ratio to water and is dimensionless. Converting a specific gravity of 0.8 to density still requires choosing the water reference density (often 1000 kg/m³) before unit conversion. Enter the resulting density, then use the Density Converter for unit labels.
FAQ
How do I convert kg/m³ to g/cm³?
To convert kg/m³ to g/cm³, divide by 1000. For example, 1000 kg/m³ ÷ 1000 = 1 g/cm³. The Density Converter divides by that factor and shows the working.
How do I convert g/cm³ to kg/m³?
To convert g/cm³ to kg/m³, multiply by 1000. For example, 2.7 g/cm³ × 1000 = 2700 kg/m³. The Density Converter multiplies by 1000 for that pair.
What is the density of water in these units?
Water is about 1000 kg/m³ or 1 g/cm³ at the usual metric reference. The Density Converter treats those as matching values when converting between the two units.
Is this a density physics calculator?
No. A physics density calculator computes density from mass and volume. The Density Converter only converts density units such as kg/m³ and g/cm³ for a value you already have.
How do I convert to lb/ft³?
Enter the density in a metric unit and choose lb/ft³ as the target. The Density Converter applies audited mass and volume factors through SI and shows the factor path on the result.
Does g/mL equal g/cm³?
For ordinary liquid measure, 1 mL is treated as 1 cm³, so g/mL and g/cm³ match numerically. The Density Converter follows that identity when both labels appear.
Why do fuel sheets use lb/gal?
US fuel and chemical trade often prices and specifies products by the gallon, so density appears as mass per gallon. The Density Converter converts lb/gal to SI when the gallon definition on the sheet matches the unit selected in the tool.
Can specific gravity be converted directly?
Specific gravity is a ratio, not a density unit. Multiply specific gravity by the reference water density (often 1000 kg/m³) to get density, then use the Density Converter to change density units.
Summary
The Density Converter converts density units through SI kilograms per cubic metre, including the exact factor of 1000 between kg/m³ and g/cm³. Imperial labels such as lb/ft³ and lb/gal use audited factors on the same page. Water at about 1000 kg/m³ (1 g/cm³) is the usual mental reference.
The tool does not compute density from mass and volume; it only changes the unit on a known density value.