Spring Rate Calculator (Helical Compression)
This tool is designed for reference purposes only in order to help determine an approximate rate of existing unmarked helical round wire compression coil springs. There are many variables which are not represented in in these calculations, therefore results are estimates and may vary.
Dual / Triple Rate Spring Calculator
Use this calculator when two or three springs are installed in series. While multiple springs are active, the combined rate is lower than any individual spring rate.
Combined Rate = 1 ÷ (1/K1 + 1/K2 + Optional 1/K3)
The calculator displays one combined rate. Use the result selector to convert it between lbs/in, N/mm, and kg/mm.
As a spring reaches coil bind or is removed by a crossover stop, calculate the next stage using the remaining active springs. When only the main spring remains active, its individual rate applies.