Spring Constant Calculator

About this calculator

This calculator applies Hooke's law, k = F / x, to find a spring's stiffness: the force applied divided by how far the spring stretches or compresses from its resting length. A higher k means a stiffer spring that resists deformation more strongly.

Mechanical and automotive engineers use it to design suspensions, valves and mattresses; physics students use it in lab experiments measuring force versus displacement; and hobbyists use it to match a replacement spring to a project. Just enter the applied force and the resulting displacement.