Work out spring potential energy instantly with clear inputs, formula shown and shareable results.
Hooke's law makes force proportional to extension, so the work done stretching a spring is the area under a triangle: E = kx^2/2. A 250 N/m spring pulled 0.12 m stores 1.8 J while pulling back with 30 N. Because energy goes as extension squared, doubling the stretch takes four times the energy - three times more again from where you are.
Stored energy
E = 0.5 k x^2
Hooke's law
F = k x
Because the force builds from zero to kx as you stretch. The average force is half the final one, and work is average force times distance.
Only within the elastic limit. Beyond it the spring yields, Hooke's law fails and some energy does not come back.