About this tool
Hooke's Law & Spring Calculator is a free, in-browser tool for ideal springs. Choose whether to solve for force, spring constant or displacement, enter the other two, and it returns the answer along with the elastic potential energy stored. All computation happens locally in your browser.
It applies Hooke's law F = k·x, where F is the restoring force, k the spring constant (stiffness) and x the displacement from equilibrium. Rearranged, k = F/x and x = F/k. The elastic potential energy stored in the stretched or compressed spring is U = ½·k·x². An optional combine mode computes an effective stiffness for two springs: in series 1/k = 1/k₁ + 1/k₂, in parallel k = k₁ + k₂.
Use it to size a spring, find the force at a given stretch, or check the energy stored. Enter force in newtons, spring constant in newtons per metre and displacement in metres, giving energy in joules.
Frequently asked questions
What is Hooke's law?
It states that the force a spring exerts is proportional to its displacement from equilibrium: F = k·x. The constant k, the spring constant or stiffness, measures how much force is needed per metre of stretch or compression.
How is elastic potential energy calculated?
The energy stored in a stretched or compressed spring is U = ½·k·x². It equals the area under the force-displacement line, and it is returned in joules whenever a displacement is available.
How do series and parallel springs combine?
Springs in series are softer overall: 1/k = 1/k₁ + 1/k₂. Springs in parallel are stiffer: k = k₁ + k₂. Turn on the combine option and enter the two spring constants to use the effective stiffness.
Does Hooke's law always hold?
Only within a spring's elastic limit. Stretch it too far and it deforms permanently or the force becomes non-linear, so the formula no longer applies. This tool models the ideal linear region and runs entirely in your browser.
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