Density Calculator
Calculate density from mass and volume in kg/m³, g/cm³ and lb/ft³, with the specific gravity and whether the material floats in water.
How much stuff is packed into the space — and whether it sinks.
How the density calculator works
Density is mass divided by volume. Water is about 1,000 kg/m³ (1 g/cm³), which is why specific gravity — density relative to water — is such a handy number: below 1 floats, above 1 sinks. Enter the mass in kilograms and the volume in liters (a liter is a cubic decimeter, so kg/L equals g/cm³).
Typical values: cork 240, pine 500, ice 917, water 1,000, concrete 2,400, aluminium 2,700, steel 7,850, lead 11,340, gold 19,300 kg/m³.
Formula: ρ = m ÷ V
Worked examples
| Inputs | Density | Note |
|---|---|---|
| 0.8 kg in 1 L | 800 kg/m³ | floats — like oil or pine |
| 2.7 kg in 1 L | 2,700 kg/m³ | aluminium |
| 0.917 kg in 1 L | 917 kg/m³ | ice floats with 92% under water |
FAQFrequently asked questions
Why does ice float?
Water expands as it freezes, so ice is about 8% less dense than liquid water. That is also why pipes burst.
What is specific gravity?
Density divided by the density of water. It has no units and reads directly as "floats or sinks": below 1 floats.
How do I measure the volume of an odd shape?
Submerge it in water and measure the rize — Archimedes' method. The displaced volume in milliliters is its volume in cubic centimeters.
Why do ships float when steel sinks?
A hull encloses air, so the average density of the whole ship is below water's. Density is about the object as a whole, not its material.
Where these figures come from
- NIST — CODATA 2018 fundamental physical constants — G, g₀, R, c
- NIST Special Publication 811 — Guide for the use of the International System of Units — unit conversions
- The Engineering ToolBox — material properties — specific heats, expansion coefficients, densities
- National Institute of Standards and Technology — the US measurement authority
Last checked: September 2026. Constants are the CODATA 2018 values; formulas are the standard textbook forms.