kN/m³
kilonewton per cubic meter
Unit weightexact by definition
The kilonewton per cubic metre is exactly 1000 N/m³, an exact prefix relation. It is the standard unit of soil unit weight in geotechnical engineering: water is 9.81 kN/m³, most soils fall between 16 and 22 kN/m³, and concrete is about 24 kN/m³.
Watch out: Soil reports distinguish bulk unit weight, dry unit weight, saturated unit weight and submerged (effective) unit weight, and they can differ by 10 kN/m³ or more for the same soil. Submerged unit weight is the saturated value minus that of water, and using the wrong one is a standard source of error in earth pressure and bearing capacity calculations.
| 1 kN/m³ | 1 kN/m³ |
Solvers that use unit weight