Spring Constant Calculator

Inputs

View results
Load applied at the first measured point.
N
Measured length (or deflection) under the first load. The slope is the same either way.
mm
Load applied at the second measured point.
N
Measured length (or deflection) under the second load.
mm

Results

Default result
Edit inputs
Spring constant(k)
2N/mm

Force per unit deflection — the same anywhere on a linear spring.

Slope of the load–deflection line.

Also computed

Force change(ΔF)40N

Deflection change(Δx)20mm

Method notes 3 notes
  • Spring constant k = (F₂ − F₁) / |x₂ − x₁| — the slope of the force–deflection line (Hooke's law).
  • Assumes a linear (constant-rate) spring; pick two well-separated points for accuracy.
  • To get the rate from spring geometry instead, use the spring rate calculator.

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