Density Converter
Convert between kg/m³, g/cm³, lb/ft³ and other density units.
What the Density Converter does
Density is mass divided by volume. Water is the handy reference at 1,000 kg/m³ or 1 g/cm³, so anything denser than 1 g/cm³ sinks in water and anything lighter floats.
Formula
Convert to kilogram per cubic metre, then divide by the target unit's factorResult = Value × (from factor ÷ to factor)
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Value | number | Yes | — |
| From | one of 7 options | Yes | — |
| To | one of 7 options | Yes | — |
How to use it
- Choose From and To.
- Enter Value.
- Select Calculate.
Worked example
Convert steel at 7,850 kg/m³ to g/cm³.
- Value
- 7850
- From
- kg/m³
- To
- g/cm³
7,850 ÷ 1,000 = 7.85 g/cm³.
Reading the result
- Water at 1 g/cm³ is the reference point: anything denser sinks in it and anything lighter floats. Steel is about 7.85, aluminium 2.7, petrol 0.75.
- 1 g/cm³ and 1,000 kg/m³ are the same density written two ways, which is why those two figures look a thousand apart.
Assumptions and limitations
- Density changes with temperature and pressure, sharply so for gases. A single figure describes one set of conditions.
Common mistakes
- Quoting specific gravity as a density. Specific gravity is a ratio against water and carries no units, so a specific gravity of 7.85 means 7,850 kg/m³.
- Mixing US and imperial gallons in pounds per gallon, which differ by about a fifth.
Frequently asked questions
What is specific gravity?
Density relative to water. Steel at 7.85 g/cm³ has a specific gravity of 7.85 — it is 7.85 times denser than water.