How do you design a compression spring?

General considerations regarding the design and calculation for a compression spring.

We design and calculate compression springs every day, so we often come across the same questions. Here we will go through the construction of a compression spring, and explain what parameters need to be defined.

Compression spring material

First define the material that matches your purpose and design. For correct calculation of your compression spring, the material should serve as the starting point.

Examples of the most commonly used spring materials.

Name Description Application Note
Piano wire Untreated "raw" spring wire
Indoors, in a dry and stable environment
Provides no protection against corrosion
Piano wire pre-galvanised Hot-dip galvanised at the wire factory Outdoor environment

No galvanisation where the wire is cut

Piano wire electro-galvanised

Piano wire post-treated in an
electro-galvanisation process

Light rust protection - nice, shiny surface Fragile surface - where rust can get under the surface
Stainless steel spring wire 302 or 304 stainless steel spring wire Outdoor environment Can be electropolished to achieve a shiny surface
Acid-proof stainless steel spring wire 316 stainless steel spring wire More aggressive environments Can be electropolished to achieve a shiny surface


Trykfjeder udvalg

Compression spring wire diameter

The force of a compression spring is defined by a combination of the thickness of the wire, its diameter, the number of coils and its free length. The thinner the wire used, the less force and stability there is in the spring. Thin wire, big diameter and many coils result in an unstable spring with a flat force curve. Thick wire, small diameter and few coils result in a steeply increasing force curve and short travel.

If you increase the diameter of a wire it has a big impact on the force, since the area is increased markedly.  

Compression spring diameter

If a compression spring has to operate over a mandrel, the inside diameter is the starting point. If the working hole for the compression spring is not variable, the outside diameter is the starting point. The diameter of a compression spring will be increased when the spring is compressed. This increase is commensurate with the pitch of the compression spring. The greater the pitch, the greater the increase in diameter. It is therefore important to know the tolerance of the outside diameter and to take account of this in the design of the spring and its construction.

Hole _vs _Rod

If the diameter of the spring is increased, the force of the spring is reduced.

Compression spring length

If possible, in your assembly, use a spring with as little travel as possible, in order to prolong the service life of the spring.

Short spring
, here maximum travel is used = short service life

Long spring, here minimum travel is used = long service life

If you increase the length of the spring, maximum force is retained, but the spring constant is reduced.

Compression spring coils

Few coils = short travel

Many coils = long travel

A big gap between coils = steep coil = steep force curve. Long travel not given, as tension in the wire reaches maximum more quickly due to few coils.

Small gaps between coils = short travel before coils touch one another. Flat force curve.

If the number of coils is increased, the force of the spring is reduced.


Compression spring end

The end of a compression spring may be one of the following.

1 Not closed 2 Closed not ground 3 Closed and ground
Trykfjeder ikke nedlagt Trykfjeder nedlagt uden slib Trykfjeder nedlagt med slib

Compression spring direction of wind

Left-hand wound Right-hand wound
Venstreviklet Hoejreviklet


 Button Tryk _UK   Button FAQ_UK 



Do write us!
If you have any questions, please contact us through this formular or send us an email

We will get back to you as soon as possible!


Our customers are the best judges!
Your opinion is highly valued. Any comment is much appreciated!


Cookie information

This website uses cookies.

By continuing to use the website, you are giving your consent to the use of cookies.

Read more here…