Elastic Potential Energy Calculator

About this calculator

This calculator uses Hooke's law energy formula, PE = ½kx², where k is the spring constant (stiffness, in N/m) and x is the displacement from the spring's natural resting length. Because the restoring force grows linearly with displacement, the stored energy grows with the square of it — stretching a spring twice as far stores four times the energy.

Mechanical engineers use it to size springs in suspensions, valves and mattresses so they store or release the right amount of energy, and physics students use it to verify energy conservation in problems like a mass launched by a compressed spring or a bungee cord's stretch at the bottom of a jump.