Kilograms per cubic metre to pounds per cubic foot (kg/m³ to lb/ft³)

The formula

lb/ft³ = kg/m³ × 0.06242796058

Where the factor comes from — each unit by its definition, then its size in SI:

• 1 kg/m³ is the SI unit of density.
• 1 lb/ft³ = lb / ft³ = 16.018463374 kg/m³

Dividing the two SI sizes gives the factor: 0.0624279605761 (rounded for display; the underlying ratio is fixed by the definitions). The reverse factor is 16.018463374.

Density is mass per volume. 1 g/cm³ is exactly 1000 kg/m³ — water is close to that — and the buoyancy and pressure formulas take kg/m³.

Worked examples

• Water at room temperature (approximately) (1 g/cm³): 1,000 kg/m³ = 62.428 lb/ft³ — 1,000 × 0.06242796058 = 62.428
• Typical structural steel: 7,850 kg/m³ = 490.059 lb/ft³ — 7,850 × 0.06242796058 = 490.059
• Air at sea level (ISA): 1.225 kg/m³ = 0.0764743 lb/ft³ — 1.225 × 0.06242796058 = 0.0764743

Frequently asked questions