What this calculator does
The density formula is mass divided by volume, written as density equation rho equals m over V, but the units a density is expressed in vary a lot between contexts: engineering and physics tend to use kg/m³, cooking and lab work use g/mL or g/cm³, and some US sources still use lb/ft³.
This calculator converts a density value between the most common units: g/cm³, kg/m³, kg/L, g/mL, lb/ft³ and oz/in³. Because g/cm³, g/mL and kg/L are all numerically identical to each other, converting between those three is a straight 1:1 read-across, while kg/m³ and the imperial units need an actual scale factor.
The formula
Every unit converts through kg/m³ as the base: g/cm³, g/mL and kg/L are each 1000 times larger than kg/m³ (so 1 g/cm³ = 1000 kg/m³), 1 lb/ft³ equals 16.0185 kg/m³, and 1 oz/in³ equals 1729.994 kg/m³. Converting from one unit to another means multiplying by the first unit's factor to reach the kg/m³ base, then dividing by the target unit's factor.
| Term | Meaning |
|---|---|
| Density (ρ) | Mass per unit volume: how much a fixed volume of a substance weighs. The density formula is ρ = m ÷ V. |
| kg/m³ | The SI base unit for density, used as the common reference point this calculator converts every other unit through. |
| g/cm³ = g/mL = kg/L | Three different-looking units that are numerically identical to each other, since a cubic centimetre, a millilitre and one-thousandth of a litre are all the same volume. |
The inputs explained
| Field | What to enter |
|---|---|
| Density value | The density value to convert. |
| From unit | The unit the value is currently in. |
| To unit | The unit to convert the value into. |
When to use it
Converting a material spec sheet between unit systems
An engineering or material datasheet given in kg/m³ converts to g/cm³ for a lab context, or to lb/ft³ when comparing against an older imperial reference or a US-sourced document.
Checking whether an object sinks or floats
Converting a density into the same units as water (1000 kg/m³, or 1 g/cm³) makes a direct comparison straightforward: anything denser sinks in water, anything less dense floats.
Working the density formula and the associated units together
After solving the density equation ρ = m ÷ V from a mass and volume elsewhere, the result often needs converting into whatever unit a report, textbook question or spec sheet expects.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How do common material densities convert from kg/m³ to g/cm³?
A spread of everyday material densities in kg/m³, converted to g/cm³.
| Material | Converted value | Relative to water (1000 kg/m³) |
|---|---|---|
| Water (1000) | 1 g/cm³ | 1.000×: neutral |
| Aluminium (2700) | 2.7 g/cm³ | 2.700×: sinks |
| Steel (7850) | 7.85 g/cm³ | 7.850×: sinks |
| Mercury (13600) | 13.6 g/cm³ | 13.600×: sinks |
| Ice (920) | 0.92 g/cm³ | 0.9200×: floats |
| Gold (19300) | 19.3 g/cm³ | 19.300×: sinks |
How does 1000 kg/m³ (water) look in every supported unit?
Water's standard density of 1000 kg/m³, shown converted into each of the other units this calculator supports.
| Target unit | Converted value |
|---|---|
| g/cm³ | 1 g/cm³ |
| kg/L | 1 kg/L |
| g/mL | 1 g/mL |
| lb/ft³ | 62.42781784 lb/ft³ |
| oz/in³ | 0.57803669 oz/in³ |
Questions
What is the density formula?
Density (ρ) equals mass divided by volume: ρ = m ÷ V. Rearranged, mass = density × volume, and volume = mass ÷ density.
What is the density equation used for?
It links how much something weighs to how much space it takes up, used for checking whether a material sinks or floats, identifying an unknown substance, or converting between mass and volume for a known material.
Are g/cm³, g/mL and kg/L the same?
Yes, all three are numerically identical, because a cubic centimetre, a millilitre and one-thousandth of a litre are the same volume. A density of 1 g/cm³ is also 1 g/mL and 1 kg/L.
How do I convert kg/m³ to lb/ft³?
Divide the kg/m³ figure by 16.0185. For example, 1000 kg/m³ (water) divided by 16.0185 gives about 62.4 lb/ft³.
To solve for density, mass or volume from the other two rather than convert a unit, see the density calculator. For a mass and volume conversion of a specific liquid instead, see the mg to mL calculator.