Density Converter Free Online
Convert density between metric and imperial units. SI base is kg/m³. Water at 4°C is 1000 kg/m³ = 1 g/cm³ = 1 g/mL = 62.43 lb/ft³.
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Density Converter Features
SI & Imperial
Cleanly converts between metric (kg/m³, g/cm³, g/mL) and imperial (lb/ft³, lb/in³, lb/gal, oz/in³).
Water Reference
Water at 4°C = 1.000 g/cm³ = 1000 kg/m³ = 62.43 lb/ft³ = 8.345 lb/gal (US). The reference for specific gravity.
9 Units
Covers chemistry (g/mL), engineering (kg/m³, lb/ft³), and material density specs (lb/in³, oz/in³).
Live Conversion
Type a value, see all units instantly.
Swap Units
Quick reverse with the swap button.
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Free vs Pro
| Feature | Free | Pro |
|---|---|---|
| Full density conversion | ||
| Live conversion | ||
| All-units result panel | ||
| Bulk CSV / Excel conversion | — | |
| REST API access | — | |
| Custom precision settings | — |
Frequently Asked Questions
Pure water at 4°C is exactly 1000 kg/m³ = 1.000 g/cm³ = 1 g/mL by historical definition. At 25°C it is slightly less (~997 kg/m³).
Carbon steel ≈ 7850 kg/m³ = 7.85 g/cm³ = 490 lb/ft³. Stainless steel is similar. Iron is 7874 kg/m³.
Density of a substance divided by the density of water (typically water at 4°C, 1000 kg/m³). Specific gravity is unitless. Mercury SG = 13.5; gasoline SG = 0.74.
Multiply by 1000. So 2.7 g/cm³ (aluminum) = 2700 kg/m³. The conversion is exact since 1 g = 0.001 kg and 1 cm³ = 10⁻⁶ m³.
Dry air at sea level, 15°C ≈ 1.225 kg/m³ = 0.0765 lb/ft³. About 800× less dense than water. At cruise altitude it drops to ~0.4 kg/m³.