Definition: Spring tension, in the context of an extension spring, is a measurement of the force it exerts.

Extension springs  come preloaded, meaning they already store force between their coils before extending. This initial tension needs to be considered when calculating the spring's working loads. To accurately determine spring tension, you'll need to factor in both the spring rate and this additional initial tension.

Spring Tension Calculation

One way to calculate spring tension is by using our spring calculator, Spring Creator 5.0  which can provide values for initial tension, spring rate, and working loads. Alternatively, you can measure spring tension with a simple scale. Initial tension becomes exhausted when the extension spring's coils extend to the point where you can see light in between the coils.

Calculating Spring Rate This diagram illustrates how to calculate your spring's rate using values from your working loads and the initial tension. To determine the rate, subtract the initial tension from the load and then divide the result by the distance traveled from the length inside hooks to the total extended length.