Compression Spring Calculations


Welcome to the coil spring rate calculation page.

Number of Active Coils:
Wire Diameter: in mm
Outside Diameter of Spring: in mm
Free Length: in mm
Compressed Length: in mm
Spring Rate: lb/in N/m kg/m
Pressure at compressed length: lb N kg


spring rate =
modulus of spring steel X wire diameter4
8 X number of active coils X mean coil diameter3

modulus of spring steel = 11,250,000 lb/in2 = 78,500 N/mm2