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Calculation Machine

Spring Constant Calculator

Hooke's law force, extension and energy.

Reviewed by James Whitfield · How we check our maths

Your values

ⓘ Live results

Results
Force
30 N
Stored energy
1.8 J
Extension under mass
0.1177 m
Oscillation period
0.688 s

Quick answer

Hooke's law says force is proportional to extension for an ideal spring.

The formula

F = kx; E = ½kx²

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Spring constant250 N/m
  • Extension0.12 m
  • Attached mass3 kg

Result

  • Force30 N
  • Stored energy1.8 J
  • Extension under mass0.1177 m
  • Oscillation period0.688 s

How to use the Spring Constant Calculator

  1. 1Enter the spring constant in N/m.
  2. 2Enter the extension or compression.
  3. 3Add a mass to see static deflection and period.

Frequently asked questions

Does Hooke's law always hold?

Only below the elastic limit — beyond it the spring deforms permanently.

How do I measure k?

Hang a known mass and divide its weight by the extension.

About this calculator