Enter the open pressure, seat pressure, and the lift height into the calculator to determine the valve spring rate.

Valve Spring Rate Formula

The following equation is used to calculate the Valve Spring Rate.

VSR = (OP-SP) / L
  • Where VSR is the valve spring rate (lbs/in)
  • OP is the open pressure (lbs)
  • SP is the seat pressure (lbs)
  • L is the lift (in)

To calculate a valve spring rate, subtract the seat pressure from the open pressure, then divide by the lift.

What is a Valve Spring Rate?


A valve spring rate is the amount of pressure needed to compress the valve spring. Valve springs are used in internal combustion engines and come in various load ratings. The load rating is how much pressure it takes to compress the spring by 1 inch. Most valve springs are rated at a maximum pressure and are measured in pounds per square inch (PSI).

How to Calculate Valve Spring Rate?

Example Problem:

The following example outlines the steps and information needed to calculate Valve Spring Rate.

First, determine the open pressure. In this example, the open pressure is 100 lbs.

Next, determine the seat pressure. This is found to be 50 lbs.

Next, determine the lift. The lift is measured to be .456 inches.

Finally, calculate the valve spring rate using the formula above:

VSR = (OP-SP) / L

VSR = (100-50) / .456

VSR = 109.64 lbs/in