N/m
newton per meter
Spring constantSurface tensionexact by definition
The newton per metre is the SI unit of stiffness, the force required per metre of deflection. Its factor is 1 by construction and the unit is exact. It is the \(k\) in Hooke's law, and also the unit of a torsion-free axial spring rate, a soil subgrade modulus per unit length and a beam's point stiffness.
| 1 N/m (Spring constant) | 1 N/m |
| 1 N/m (Surface tension) | 1,000 mN/m |
As a unit of surface tension
The newton per metre is the SI unit of surface tension, the force per unit length along a surface, and equivalently the surface energy per unit area in joules per square metre. Its factor is 1 by construction. It is a large unit for the phenomenon: water is only 0.0728 N/m at 20 °C.
Solvers that use spring constant