Attention! Input results shown will be +/- 10% from middle value. Hint: The closer your min and max inputs are, the more accurate your results will be!

Attention! Input results shown will be +/- 10% from middle value. Hint: The closer your min and max inputs are, the more accurate your results will be!

Attention! Input results shown will be +/- 10% from middle value. Hint: The closer your min and max inputs are, the more accurate your results will be!

Attention! Input results shown will be +/- 10% from middle value. Hint: The closer your min and max inputs are, the more accurate your results will be!

Coil Spring Solid Height

Definition - The height of a spring when it is fully compressed and all of its coils are touching one another. At this point no more force/energy can be gathered by the spring.

When a load is placed on a coiled spring causing it to compress, it gathers force and energy. After the load is removed, this gathered energy causes the spring to extend back to its original length. This is known as memory.

The distance from the free length to solid height is known as distance traveled. Distance traveled is the length of deflection that a spring is able to perform.

For example:

Let’s say you have a spring with a 1” (inch) free length and a solid height of 0.25” (inches). The distance traveled from free length to solid height is of 0.75” (inches). You solve this by subtracting the solid height from the free length thus getting the potential distance of travel.

Why do we say potential distance of travel?

Compression springs have an elastic limit based on their physical dimensions. If a compression spring is too stressed (too strong), it might not be able to deflect down to solid height. When a coil spring is very light you can get more travel by extending the free length, and still be able to compress it down to solid height.

free length compressed to solid height

To Calculate Solid Height for Closed and Squared, Double Closed or Open Ends

Solid Height is based on two of your spring’s dimensions; wire diameter and total coils. To calculate this dimension, you must add 1 to the total coils and multiply the result by the wire diameter. The reason we add one is to account for the additional wire to not included in the to the total coil count. This is only for closed and square ends, double closed ends, and open ends. The formula below as well as the diagram to the right show how it works.

Sh = (Tc + 1) x WD
Solid Height = (Total Coils + 1) x Wire Diameter

For example

In this scenario we have a spring with a 0.5” (inch) wire diameter and 4 total coils. We added 1 wire to the 4 coils, this gives us 5, which we multiplied by 0.5 and we get 2.5 as a result. The solid height of this spring would be 2.5 inch.

Sh = (Tc + 1) x WD
Sh = (4 + 1) x 0.5
Sh = 5 x 0.5
Sh = 2.5 inch.

solid height formula for springs with closed ends

To Calculate Solid Height - Ground Ends

When a spring’s ends are ground, you are taking off half of the wire diameter on each end, therefore the solid height will be shorter. Due to this there is no need to add the additional wire diameter. To calculate this dimension on a spring with ground ends, you would simply multiply the total coils by the wire diameter as shown in the formula below.

Sh = Tc x WD
Solid Height = Total Coils x Wire Diameter

For example

Take the same spring with a 0.5” (inch) wire diameter and 4 total coils. The solid height of this spring would be 2” since we multiplied 0.5.

Sh = Tc x WD
Sh = 4 x 0.5
Sh = 2

solid height formula for springs with ground ends