The density formula
Density is how much mass is packed into a given volume.
Density = mass ÷ volume · Mass = density × volume · Volume = mass ÷ density
The calculator converts everything to kilograms and cubic meters first, so you can mix units.
Worked example
A block weighs 500 g and takes up 250 cm³. Its density is 500 ÷ 250 = 2 g/cm³, which is 2,000 kg/m³. That's twice as dense as water, so it sinks. Going the other way, 100 cm³ of iron at 7.87 g/cm³ has a mass of 7.87 × 100 = 787 g.
Densities of common materials
| Material | kg/m³ | g/cm³ | lb/ft³ |
|---|---|---|---|
| Air (20 °C, sea level) | 1.204 | 0.001204 | 0.0752 |
| Water (20 °C) | 998 | 0.998 | 62.3 |
| Ice | 917 | 0.917 | 57.2 |
| Concrete (typical) | 2,400 | 2.4 | 150 |
| Aluminum | 2,700 | 2.7 | 169 |
| Steel (carbon, typical) | 7,850 | 7.85 | 490 |
| Iron | 7,870 | 7.87 | 491 |
| Copper | 8,960 | 8.96 | 559 |
| Silver | 1.05e+04 | 10.5 | 655 |
| Lead | 1.13e+04 | 11.3 | 705 |
| Gold | 1.93e+04 | 19.3 | 1.2e+03 |
Pure elements are from the Royal Society of Chemistry's periodic table (at room temperature). Water and ice are from the USGS. Air, steel and concrete are typical values: air depends on temperature and pressure, and steel and concrete depend on the mix.
Limitations
- Density changes with temperature, a lot for gases and a little for liquids and solids.
- Loose materials like sand, soil and gravel have a bulk density that includes the air between the grains, so it's much lower than the density of the rock itself.
- Mass and weight are different things, but on Earth a mass in kg or lb is what a scale shows.