Density Converter
Convert density between kg/m³, g/cm³, g/mL, lb/ft³, and lb/gal.
Water is 1 g/cm³ and aluminum is 2.7 g/cm³.
Used in material science and fluid dynamics.
Type in any field — the others update instantly.
Density Conversion uses kg/m³ as the base unit.
Key relationships:
1 g/cm³ = 1,000 kg/m³1 lb/ft³ = 16.0185 kg/m³1 lb/gal (US) = 119.826 kg/m³
Common material densities:
- Air (sea level): 1.225 kg/m³ = 0.001225 g/cm³
- Water (4°C): 1,000 kg/m³ = 1.000 g/cm³ = 62.43 lb/ft³ = 8.345 lb/gal
- Concrete: 2,400 kg/m³ = 2.4 g/cm³ = 149.8 lb/ft³
- Steel: 7,850 kg/m³ = 7.85 g/cm³ = 490 lb/ft³
- Aluminum: 2,700 kg/m³ = 2.7 g/cm³ = 168.6 lb/ft³
- Gold: 19,300 kg/m³ = 19.3 g/cm³
Specific gravity is density relative to water: SG = density / 1000 kg/m³
Density is what tells you whether something floats. Anything less dense than water (under 1 g/cm³) floats; anything denser sinks. That’s the whole story behind a block of wood bobbing while a steel bolt drops, and it’s why specific gravity, density compared to water, is such a useful shorthand: a specific gravity below 1 floats, above 1 sinks.
Two practical notes. The g/cm³ scale is popular precisely because water sits at almost exactly 1, which makes mental comparisons easy. And density isn’t perfectly fixed, it shifts with temperature: most materials expand and grow slightly less dense as they warm, so a density figure for a liquid or gas is usually quoted at a stated temperature. For gases the effect is dramatic, which is part of why they’re handled by mass rather than volume.
How we build and check this converter
This converter runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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