the Spring rate , also called spring constant or spring stiffness, depends on the material and shape of the spring. The calculation formula for cylindrical springs made of round wire with a linear spring characteristic is as follows:

Compression spring spring rate / spring constant (N / mm) Formula collection compression springs

Formula spring constant compression springs

Tension spring spring rate / spring constant (N / mm) Formula collection extension springs

Formula spring constant tension springs

Leg spring spring torque rate (Nmm) ( Collection of formulas torsion springs)

Formula torque rate torsion springs

Overview of the spring materials

∝ = angle of rotation (°)
d = wire diameter (mm)
D = mean coil diameter (mm)
E = modulus of elasticity (N / mm²)
F = spring force (N)
M = torque (Nmm)
s = spring deflection (mm)
n = resilient coils (n)
G = sliding or shear modulus (N / mm²)

For more information:

Calculate spring rate for cylindrical springs