Calculating Constant Force on a Coil Compression Spring


The calculation of the amount of constant force it takes a coil compression spring to compress down to a loaded height is calculated by multiplying the force by the distance the coil compression spring is expected to travel. The unit of measurement for constant force is lbf/in which stands for pounds of force per inch.

The above compression spring calculator will help you make these coil compression spring calculations. Not only will you see the results of your coils spring’s rate or constant but you will also see the safe maximum amount of load you will be able to place on your coil spring as well as the maximum travel considering solid height. Most of the time, you will be able to travel safely down to your coil compression spring’s solid height but there are times that your spring design will not safely travel that far. This is due to the spring’s physical dimensions (too little coils or a small index) and the elasticity of the spring wire.


A spring of 12” (inches) has to travel 5” to a loaded height of 7” with a load or force of 5 lb. (pounds).

k = F ÷ x
k = 5 ÷ 5
k = 1 lbf/in (pounds of force per inch)

F = Force
x = Distance Traveled
k = Constant or Rate