Calculate spring pressure and force from spring rate, compression, and contact area or diameter, with results in Pa, psi, N, and lbf.

Average contact pressure for a linear spring with no preload. Use the loaded contact area, not the spring wire cross-section.

Spring Pressure Formula

For a linear spring with no preload, the following formula gives average pressure over the loaded contact area. It does not calculate peak contact stress or spring-wire stress.

Pspring = K ร— X / A
  • Where Pspring is the Spring Pressure (Pa)
  • K is the spring rate (N/m) 
  • X is the compression (m) 
  • A is the loaded contact area (m^2), not the spring wire cross-section 

Multiply spring rate by compression from the unloaded length to get force, then divide by loaded contact area. For a circular contact, A = ฯ€dยฒ/4 using its contact diameter. The calculator also solves for rate, compression or area; selected units are converted before calculation.

How to Calculate Spring Pressure?

The following example problems outline how to calculate the Spring Pressure.

Example Problem #1

  1. First, determine the spring rate (N/m). In this example, the spring rate (N/m) is given as 100.
  2. Next, determine the compression (m). For this problem, the compression (m) is given as  .5.
  3. Next, determine the loaded contact area (m^2). In this case, the loaded contact area (m^2) is found to be .75.
  4. Finally, calculate the Spring Pressure using the formula above: 

Pspring = K * X / A

Inserting the values from above and solving yields: 

Pspring = 100 * .5 / .75 = 66.67 (Pa)

Example Problem #2

Using the same method as above, determine the variables required by the equation. For this example problem, these are provided as:

spring rate (N/m) = 500

compression (m) = 3

loaded contact area (m^2) = 5

Entering these given values yields: 

Pspring = 500 * 3 / 5 = 300 (Pa)