Hookes Law
Calculator

It describes the restoring force a spring (or any elastic material) exerts when stretched or compressed by a distance x, where k is the spring constant — a measure of the spring's stiffness in newtons per meter. A larger k means a stiffer spring that requires more force to deform by the same distance.

Hooke's law only holds within a spring's elastic region, where deformation is directly proportional to force and the spring returns to its original shape once the force is removed. Beyond the elastic limit, the material deforms permanently (plastic deformation) or breaks, and the simple linear F = kx relationship no longer accurately predicts behavior.

It's typically measured experimentally by hanging known weights on a spring and measuring the resulting extension, then calculating k as the slope of force versus extension (k = F/x) — stiffer springs used in heavy-duty applications have much higher k values than soft springs like those in a pen. Manufacturers usually specify k on the spring's datasheet as well.

Yes, for an ideal spring — the same formula and spring constant apply whether the spring is compressed or stretched, with the restoring force always acting to return the spring toward its natural, unstretched length. Some real springs behave slightly asymmetrically in compression versus tension, but the ideal Hooke's law model treats both directions identically.

The force from Hooke's law varies continuously as displacement changes, so the energy stored (elastic potential energy) is found by integrating force over distance, giving PE = ½kx² rather than a simple F times x. This squared relationship means doubling the stretch quadruples the stored energy, similar to how doubling speed quadruples kinetic energy.