N/mm
newton per millimeter
Spring constantexact by definition
The newton per millimetre is exactly 1000 newtons per metre. It is the rate printed on almost every commercial spring, gas strut and vibration isolator catalogue in metric markets, and it is the natural output of a finite element model dimensioned in millimetres.
Watch out: N/mm is a thousand times N/m, and reading a 25 N/mm suspension spring as 25 N/m understates it by three orders of magnitude. N/mm is also the same number as MPa when it appears as N/mm² in stress work, which is a separate coincidence worth not conflating.
| 1 N/mm | 1,000 N/m |
Solvers that use spring constant