Hooke's Law states that the force exerted by a spring is proportional to its displacement from the rest position: F = k * x. The spring constant k (in N/m) represents the stiffness of the spring.

What units is the spring constant measured in?

The spring constant k is measured in Newtons per meter (N/m). A spring with k = 100 N/m requires 100 N of force to stretch or compress it by 1 meter.

Does Hooke's Law apply to all springs?

Hooke's Law is valid only within the elastic limit of the spring. Beyond this point, the spring deforms permanently and the linear relationship no longer holds.

What is a typical spring constant value?

Spring constants vary widely depending on the application. Small springs in pens might be around 200–500 N/m, while automotive coil springs can range from 15,000 to 50,000 N/m or more.

Can I use this for compression as well as extension?

Yes. Hooke's Law applies to both compression and extension. Use positive displacement for extension (stretching) and the calculation remains the same in magnitude.

Spring Constant Calculator

Calculate the spring constant (k) from force and displacement using Hooke's Law, or solve for any missing variable.

Inputs

Select what you want to solve for, then fill in the other two values.

Solve For

Force (F)

Displacement (x)

Spring Constant (k)

Result

Fill in the inputs and press Calculate.

Formula Reference

k = F / x — spring constant (N/m)

F = k * x — force (N)

x = F / k — displacement (m)

Summary

The Spring Constant Calculator applies Hooke's Law (F = k * x) to find any one of three variables — spring constant (k), force (F), or displacement (x) — given the other two. The spring constant, measured in Newtons per meter (N/m), describes the stiffness of a spring: a higher value means a stiffer spring that requires more force to stretch or compress. This tool is useful for physics students, engineers, and anyone working with elastic systems.

How it works

Select which variable you want to solve for: spring constant (k), force (F), or displacement (x).
Enter values for the other two variables in the input fields.
Choose the appropriate units for each measurement.
Click Calculate to instantly see the result with full working shown.
Use the Reset button to start a new calculation.

Use cases

Determine the stiffness of a spring from experimental force and extension measurements.
Calculate how much force a spring exerts at a given displacement.
Find how far a spring will compress or extend under a known load.
Design mechanical systems involving springs, such as suspension or valve mechanisms.
Verify lab results in a physics class or engineering course.
Estimate spring behavior for prototyping elastic or flexible structures.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu