Spring Rate Calculator
SI
Imp
Imperial
Inputs
View results
Wire diameter
(d)
Diameter of the spring wire.
mm
Mean coil diameter
(D)
Center-to-center across the coil (outside diameter − wire diameter).
mm
Active coils
(Nₐ)
Coils that actually deflect (total coils minus the end coils).
Material
Sets the shear modulus G.
Music wire (ASTM A228)
Oil-tempered (ASTM A229)
Hard-drawn (ASTM A227)
Chrome silicon (ASTM A401)
Chrome vanadium (ASTM A232)
Stainless 302/304 (ASTM A313)
Deflection
(x)
Working compression — used for the force at that point.
mm
Results
Default result
Edit inputs
Spring rate
(k)
6.453
N/mm
Also computed
Spring index
(C)
Pass
8
Force at deflection
(F)
129.1
N
29.02 lbf
At the deflection entered above.
Force vs Deflection
The straight load line comes from F = kx, using the calculated spring rate and the entered operating deflection.
Force vs Deflection
0
100
200
300
0
10
20
30
40
operating
Deflection (mm)
Force (N)
The straight load line comes from F = kx, using the calculated spring rate and the entered operating deflection.
Method notes
2 notes
Rate depends only on geometry and material — not on free length or end type.
For corrected stress, solid height and a buckling check, use the full compression spring calculator.
Powered by MachineCalcs ↗