Enter the compression ratio into the calculator to convert into pounds per square inch.

Compression Ratio to PSI Formula

The following formula is used to convert a compression ratio to PSI.


  • Where PSI is the pounds per square inch
  • X:Y is the compression ratio
  • P is the pressure (typically standard atmospheric pressure (14.696)

Compression Ratio to PSI Example

How to calculate psi from compression ratio?

The following example goes over the steps required to convert a compression ratio into pounds per square inch (PSI).

The first step in determining the psi is to determine the compression ratio. In this case, the compression ratio is a simple 2:1 = 2/1 = 2.

Next, determine the pressure that the engine is working at. In this case, the engine is running at standard atmospheric pressure which is equal to 14.696 PSI at sea level.

Finally, calculate the PSI using the formula above:


PSI = 2:1*14.696

PSI = 29.393 PSI.


How to do you convert a compression ratio to a PSI?

Convert a compression ratio to PSI by multiplying the atmospheric pressure by the compression ratio.