Spring Constant Calculator
Calculate spring constant, force and potential energy using Hooke's law.
Results
Hooke's law states that the force needed to extend or compress a spring is proportional to the displacement: F = kx. The spring constant k tells you how stiff the spring is - higher values mean stiffer springs. This calculator also computes the elastic potential energy stored in the spring, which is released when the spring returns to its natural length.
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Frequently asked questions
k = F/x = 10 / 0.05 = 200 N/m. This means you need 200 newtons of force to stretch this spring by 1 meter.
PE = 0.5 × k × x². A spring with k = 200 N/m compressed 5 cm stores 0.5 × 200 × 0.0025 = 0.25 joules of potential energy.
Spring constant is measured in newtons per meter (N/m). Common values range from about 10 N/m for a soft spring to over 100,000 N/m for automotive suspension springs.
Higher k means stiffer. A car suspension spring has k around 20,000-40,000 N/m. A ballpoint pen spring is about 100-500 N/m. A trampoline spring is about 4,000-8,000 N/m.
Yes. Beyond the elastic limit, the spring deforms permanently and Hooke's law no longer applies. Most springs are designed to operate well within this limit - typically at less than 75% of maximum deflection.