This density calculator solves ρ = m ÷ V for any one unknown — density, mass or volume. Enter the two values you know; get the third, with conversions between g/cm³ and kg/m³.
What Is Density?
Density is how much mass is packed into a given volume — the property that decides whether something floats, why a steel ship can float while a steel pebble sinks, and how geologists identify minerals. This calculator is part of our Physics Calculators collection.
The Density Formula
ρ (density) = m (mass) ÷ V (volume)
Worked example (verified): a sample with mass 500 g and volume 250 cm³ has density 500 ÷ 250 = 2.00 g/cm³ — twice as dense as water, in the range of common rock or glass. Rearranged, the same formula gives mass = ρ × V and volume = m ÷ ρ; the solve-for menu above handles all three.
Densities of Common Materials
| Material | Density (g/cm³) |
|---|---|
| Air (sea level) | 0.0012 |
| Ice | 0.917 |
| Water (fresh, 4 °C) | 1.000 |
| Seawater | 1.025 |
| Aluminum | 2.70 |
| Iron / steel | 7.87 |
| Copper | 8.96 |
| Lead | 11.34 |
| Gold | 19.32 |
| Osmium (densest natural element) | 22.59 |
Ice floating at 0.917 is no trivia: it insulates lakes in winter and keeps aquatic life alive underneath. Gold's extreme 19.32 is why density tests expose fake gold bars — a tungsten fake (19.25) is one of the few that come close, which is why assayers use more than density alone.
Units and Conversions
- g/cm³ and kg/m³: multiply g/cm³ by 1,000 to get kg/m³ (2.00 g/cm³ = 2,000 kg/m³). Numerically, g/cm³ also equals g/mL — handy in the lab.
- Finding volume of an irregular object: water displacement — submerge it and read the rise; that classic Archimedes method feeds straight into this calculator.
- For the energy side of moving masses, see our Kinetic Energy Calculator; for the chemistry of masses, the Molar Mass Calculator.
Related Tools
- Kinetic Energy Calculator
- Molar Mass Calculator
- Physics Calculators — the full collection
Frequently Asked Questions
How do I calculate density?
Divide mass by volume: ρ = m/V. Measure mass on a balance and volume by dimensions (regular shapes) or water displacement (irregular ones).
What is the density of water?
1.000 g/cm³ (1,000 kg/m³) at 4 °C — the reference point for the whole scale and for specific gravity.
Why do objects less dense than water float?
Buoyancy: the water displaced weighs more than the object does at the same volume, so the upward force wins. Anything with density under 1.00 g/cm³ floats in fresh water.
Does density change with temperature?
Yes — most materials expand when heated, so density falls slightly. Water is the famous exception between 0–4 °C, which is why ice forms on top of lakes.
What is specific gravity?
Density relative to water: specific gravity = density ÷ 1.00 g/cm³, a unitless number equal to the g/cm³ value.
Is this density calculator free?
Yes — free, instant, no sign-up.