Density Unit Converter (kg/m³, g/cm³, lb/ft³, lb/gal)
Convert density between kg/m³, g/cm³ (g/mL), g/L, mg/L, t/m³, lb/ft³, lb/in³, pounds per US or UK gallon and oz/in³ — for liquids, metals, concrete and lab work.
How it works
value in target unit = value × (kg/m³ per source unit) ÷ (kg/m³ per target unit) · 1 g/cm³ = 1,000 kg/m³ = 62.42796 lb/ft³ = 8.3454 lb/gal (US)
Density is mass per volume, so each unit is a mass unit divided by a volume unit; the converter goes through kilograms per cubic meter. Because 1 cm³ = 1 mL and 1 L = 1,000 cm³, g/cm³, g/mL and kg/L are the same number, and kg/m³ equals g/L. Imperial units use the exact pound (0.45359237 kg), foot (0.3048 m) and gallons (3.785411784 L US, 4.54609 L UK).
Worked example
1 g/cm³ (the density of water) × 1,000 = 1,000 kg/m³, and 1,000 ÷ 16.0184634 = 62.428 lb/ft³ — the familiar 62.4 lb per cubic foot of water.
Sources: NIST SP 811, Appendix B — Conversion factors · NIST — Unit conversion (SI and US customary)
Frequently asked questions
How do I convert g/cm³ to kg/m³?
Multiply by 1,000. Aluminum at 2.70 g/cm³ is 2,700 kg/m³; steel at 7.85 g/cm³ is 7,850 kg/m³.
What is the density of water in different units?
About 1 g/cm³ = 1,000 kg/m³ = 62.43 lb/ft³ = 8.345 lb per US gallon (at 4 °C; slightly less when warm).
Are g/mL and g/cm³ the same?
Yes. One milliliter is exactly one cubic centimeter, so 1.2 g/mL = 1.2 g/cm³ = 1.2 kg/L.
How do I convert kg/m³ to lb/ft³?
Divide by 16.0185: concrete at 2,400 kg/m³ is 149.8 lb/ft³.
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This calculator is for educational purposes. Double-check important results before acting on them.