lb/ft³ to kg/m³
A US drawing says the fill material weighs 110 lb/ft³. The metric counterpart asks for kg/m³: 1,762. The conversion factor, 16.018463, is the exact number that carries a 1959 pound over a 1959 foot cubed — and it's the same number whether you're shipping a soil spec to a European lab or checking concrete against an international standard.
kg/m³ = lb/ft³ × 16.01846337
1 lb/ft³ = 16.01846337 kg/m³ — the 1959 pound over the 1959 foot, cubed
The factor is exact — derived from SI definitions and the 1959 yard/pound agreement.
Common lb/ft³ to kg/m³ Conversions
| lb/ft³ | kg/m³ | Material / context |
|---|---|---|
| 1 lb/ft³ | 16.02 kg/m³ | The definitional anchor. |
| 37.5 lb/ft³ | 600 kg/m³ | Dry pine wood. |
| 62.4 lb/ft³ | 1,000 kg/m³ | Water — the construction anchor. |
| 110 lb/ft³ | 1,762 kg/m³ | Typical compacted soil. |
| 150 lb/ft³ | 2,403 kg/m³ | Normal-weight concrete. |
| 490 lb/ft³ | 7,849 kg/m³ | Carbon steel. |
Engineering Context
Density links the mass and volume families on this site — it is their ratio. For the mass numerator, the kg to g and lbs to kg converters carry the same 1959 constants that appear here; for the volume denominator, the liters to mL and cubic feet to cubic meters pages supply the cubed lengths. The density hub collects all ten converters in this family.
More: Kg M3 To Lb Ft3 · Lb Ft3 To G Cm3 · Kg M3 To G Cm3 · Density
Related Unit Converters
Frequently Asked Questions
How do I estimate kg/m³ from lb/ft³ quickly?
Multiply by 16. For a quick estimate, 150 lb/ft³ × 16 = 2,400 kg/m³ — the concrete number everyone remembers. The exact factor is 16.018463, so the shortcut is accurate to about 0.1%.
Why does US construction use lb/ft³?
Because the US building codes and test standards were written in customary units, and the density values became memorable: 62.4 for water, 150 for concrete, 110 for soil. The industry stays bilingual and converts.
Is 62.4 lb/ft³ water or 62.428?
62.4 is the shorthand; the exact value for water at 4 °C is 62.427961 lb/ft³. The 0.04% difference is irrelevant for concrete mix design but matters in hydrology and naval architecture.