Density Calculator
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Pick the value you want, enter the other two and the density calculator does the rest, converting between metric and US units for density, mass and volume.
Density is the amount of mass in a given volume: how tightly matter is packed. A liter of water has a mass of about one kilogram, while a liter of gold would have a mass of more than 19 kilograms. Density is a characteristic property of a material at a given temperature and pressure, which is why it is useful for identifying substances. Archimedes is said to have checked whether a king's crown was pure gold by comparing its density with that of gold.
Density also explains why things float. An object sinks in a fluid if it is denser than the fluid and floats if it is less dense, so ice, at about 917 kg/m³, floats on liquid water at about 1,000 kg/m³, and a steel ship floats because its hull encloses so much air that its average density is lower than seawater's. Hot air balloons rise because heated air is less dense than the cooler air around it.
The density of most substances changes with temperature, because they expand as they warm, and gases also change strongly with pressure. Reference values are therefore quoted at stated conditions, usually 20 °C or 25 °C and one atmosphere. Specific gravity, or relative density, is a material's density divided by that of water, so it has no units; a specific gravity of 2.7 means 2.7 times as dense as water.
Formula
ρ = m ÷ V
- ρ
- density (the Greek letter rho)
- m
- mass
- V
- volume
Rearranged: m = ρ × V and V = m ÷ ρ.
Common Density Units
The SI unit of density is the kilogram per cubic meter (kg/m³). Chemists often use grams per cubic centimeter (g/cm³), which equals grams per milliliter and kilograms per liter; water is very close to 1 in all three. In the United States, pounds per cubic foot and pounds per gallon are common in engineering and trade.
| Unit | Equals (kg/m³) |
|---|---|
| 1 g/cm³ = 1 g/mL = 1 kg/L | 1,000 |
| 1 g/L = 1 kg/m³ | 1 |
| 1 lb/ft³ | 16.0185 |
| 1 lb/in³ | 27,679.9 |
| 1 lb/gal (US) | 119.826 |
| 1 lb/gal (UK) | 99.7763 |
| 1 lb/yd³ | 0.593276 |
Density of Common Materials
Approximate densities of familiar materials at room temperature and normal atmospheric pressure. Natural materials such as wood, soil and rock vary widely with type and moisture content.
| Material | Density (kg/m³) | Density (g/cm³) |
|---|---|---|
| Air (20 °C, sea level) | 1.204 | 0.0012 |
| Gasoline | about 740 | 0.74 |
| Oak wood (dry) | about 600 – 900 | 0.6 – 0.9 |
| Ice | 917 | 0.917 |
| Water (4 °C) | 1,000 | 1.000 |
| Seawater | about 1,025 | 1.025 |
| Concrete | about 2,400 | 2.4 |
| Aluminum | 2,700 | 2.70 |
| Steel | about 7,850 | 7.85 |
| Iron | 7,874 | 7.87 |
| Copper | 8,960 | 8.96 |
| Silver | 10,490 | 10.49 |
| Lead | 11,340 | 11.34 |
| Mercury | 13,534 | 13.53 |
| Gold | 19,300 | 19.30 |
| Osmium (densest element) | 22,590 | 22.59 |
Frequently asked questions
What is the formula for density?
Density equals mass divided by volume, ρ = m ÷ V. A 270 g block of aluminum with a volume of 100 cm³ has a density of 2.7 g/cm³. Rearranged, mass = density × volume and volume = mass ÷ density.
What is the density of water?
About 1 g/cm³ or 1,000 kg/m³ at 4 °C, where water is densest. At room temperature it is about 0.998 g/cm³.
How do I convert g/cm³ to kg/m³?
Multiply by 1,000. 7.85 g/cm³ is 7,850 kg/m³.
Why does ice float?
Water expands when it freezes, so ice is about 9% less dense than liquid water and floats with roughly 90% of its volume below the surface.
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