Enter the exhaust pressure (psi) and the inlet pressure (psi) into the Pressure Ratio Calculator. The calculator will evaluate and display the Pressure Ratio. 

Pressure Ratio Formula

The following formula is used to calculate the Pressure Ratio. 

PUR = EP / IP * 100

  • Where PUR is the Pressure Ratio (%)
  • EP is the exhaust pressure (psi) 
  • IP is the inlet pressure (psi) 

How to Calculate Pressure Ratio?

The following example problems outline how to calculate Pressure Ratio.

Example Problem #1:

  1. First, determine the exhaust pressure (psi). 
    • The exhaust pressure (psi) is given as: 30.
  2. Next, determine the inlet pressure (psi). 
    • The inlet pressure (psi) is provided as: 15.
  3. Finally, calculate the Pressure Ratio using the equation above: 

PUR = EP / IP * 100

The values given above are inserted into the equation below and the solution is calculated:

PUR = 30 / 15 * 100 = 200 (%)


Example Problem #2: 

For this problem, the variables required are provided below:

exhaust pressure (psi) = 50

inlet pressure (psi) = 20

Test your knowledge using the equation and check your answer with the calculator above.

PUR = EP / IP * 100 = ?