Spring Force Calculator

How it works

1. 1Enter the spring constant k in N/m (how stiff the spring is) and the displacement x in centimetres (or inches in imperial mode).
2. 2The tool converts x to metres and applies Hooke’s law F = k·x, the magnitude of the restoring force in newtons.
3. 3The result is shown in newtons (metric) or pound-force (imperial); a stat always shows the force in N.

Use cases

• Mechanical engineering — sizing return springs in valves, latches, and actuators for a target force at a given travel.
• Physics education — verifying Hooke’s law experiments and cross-checking hand calculations.
• Product design — estimating the click force of a spring-loaded button at its designed compression.

Frequently asked questions

What is Hooke’s law?

Hooke’s law states that the restoring force F of a spring equals the spring constant k times the displacement x from its natural length: F = k·x. The force acts opposite to the displacement — that is what “restoring” means. It holds while the spring stays within its elastic limit.

What does the spring constant k represent?

The spring constant k (in N/m) is the stiffness: a higher k means a stiffer spring that needs more force for the same displacement. A soft band might have k ≈ 10 N/m; a heavy-duty spring can exceed 100,000 N/m.

Can you show a worked example?

For k = 200 N/m compressed by x = 0.05 m (5 cm): F = 200 × 0.05 = 10 N. The spring pushes back with 10 N opposing the compression — about 2.25 lbf.