Spring rate (constant) calculator
Find the spring rate (N/mm and lbf/in) of a helical spring from wire diameter, mean diameter and number of active coils.
mm
mm
mm
Result
Spring rate14.558 lbf/in [2.55 N/mm]
Max safe load14.329 lbf [63.74 N]
Max safe deflection0.984 in [25.00 mm]
Solid height0.591 in [15.00 mm]
Spring index9.00
Spring rate k = G·d⁴ / (8·D³·Na) is dominated by wire diameter (to the fourth power). Tune the parameters and watch the effect in real time.
Calculations use each catalog material's real shear modulus.