Spring Rate Calculator
Calculate spring rate and stiffness from applied force and deflection, or coil geometry, with this free mechanical calculator in your browser.
Enter Values
Minimum 0
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the force applied and the resulting deflection.
- Read the spring rate.
How it works
Spring rate k = force ÷ deflection (Hooke's law).
Worked example
100 N over 20 mm. = 5 N/mm.
Common mistakes
- Measuring deflection beyond the spring's linear range.
- Mixing units — keep force in N and deflection in mm for N/mm.
Frequently asked questions
What does spring rate mean?
How much force it takes to compress or extend the spring by one unit — higher means a stiffer spring.
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Cite this tool
Zerdly. (2026). Spring Rate Calculator. Retrieved from https://www.zerdly.com/tools/spring-rate-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.