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Compression spring rate calculator

Spring rate from wire size, coil diameter and active coils.

mm
mm
Outside diameter − wire diameter
N

Calculating…

How it's calculated

k = G × d⁴ ÷ (8 × D³ × n)

Doubling the wire diameter makes a spring 16 times stiffer; doubling the coil diameter makes it 8 times softer. Active coils exclude the closed end coils (typically total coils − 2 for squared ends).