lb/ft³
pound per cubic foot
Densityexact by definition
The pound per cubic foot converts one avoirdupois pound of mass into the volume of one cubic foot, giving 16.018463... kg/m³. The definition is exact because both the pound (0.45359237 kg) and the foot (0.3048 m) are exact, though the resulting decimal does not terminate and the stored value is rounded. Water is about 62.4 lb/ft³ and structural steel about 490 lb/ft³.
Watch out: In soil mechanics and concrete work the same numbers are often labelled pcf, which is used loosely for both pound per cubic foot (a density) and pound-force per cubic foot (a unit weight). They are numerically equal on Earth but they are different quantities, and the specific-weight version appears separately on this site.
| 1 lb/ft³ | 16.018463 kg/m³ |
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