Compression Spring Calculator

What this calculator does

This calculator performs a complete design check for cylindrical helical compression springs made from round wire. It computes the spring index, rate and stress in real time, compares the working point with the solid (compressed) height, and flags slenderness problems that can cause buckling. Every change redraws the load–deflection curve, so candidate designs can be compared before a prototype is ordered.

Inputs and outputs

Inputs

Wire diameter d (mm)
Mean coil diameter D (mm)
Active coil count n
Free length L0 (mm)
Material: music wire, stainless 304/316, 65Mn, 60Si2Mn and more
Working load or working deflection

Results

Spring rate k (N/mm)
Deflection at the working load
Shear stress compared with the material allowable
Solid length and remaining travel
Slenderness ratio with a stability warning
Load–deflection (F–f) curve

Typical applications

Valves and pumps
Fixtures, jigs and clamps
Suspension and vibration mounts
Electromechanical actuators
Consumer products and toys

Design notes

Compression springs usually fail from stress at solid height rather than at the working point. Check the stress at solid, keep the slenderness ratio below roughly 2.6 for guided springs, and confirm the allowable stress of the actual wire grade with your supplier before releasing a drawing.

The interactive calculator interface is currently in Chinese. Enter your values there, or send us the load, travel and space constraints and our engineers will return a checked calculation sheet in English.

Frequently asked questions

Is the calculator free?

Yes. All 13 design calculators on this site are free, with no login and no limit on the number of calculations.

Which units does it use?

Millimetres and newtons. Convert inch drawings to metric before entering values, or send us the drawing and we will convert it for you.

Can I print or export the result?

The tool produces a printable calculation sheet and a 3D preview. The interface is in Chinese; English-speaking engineers can send us the parameters and receive a checked calculation sheet.

Are the results suitable for production?

The results follow standard helical spring equations and are intended for preliminary design. A production design should be verified by an engineer against the applicable standard and the actual fatigue requirement.