Enter the arterial p02 (P) and the fraction percent of inspired oxygen (FI02) into the PF Ratio Calculator. The calculator will evaluate and display the PF Ratio. 

PF Ratio Formula

The following formula is used to calculate the PF Ratio. 

PFR = P/F

  • Where PFR is the PF Ratio
  • P is the arterial p02 (P) 
  • F is the fraction percent of inspired oxygen (FI02) 

How to Calculate PF Ratio?

The following example problems outline how to calculate PF Ratio.

Example Problem #1:

  1. First, determine the arterial p02 (P). 
    • The arterial p02 (P) is given as: 86.
  2. Next, determine the fraction percent of inspired oxygen (FI02). 
    • The fraction percent of inspired oxygen (FI02) is provided as: .80.
  3. Finally, calculate the PF Ratio using the equation above: 

PFR = P/F

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

PFR = 86/.80 = 107.5


Example Problem #2: 

For this problem, the variables required are provided below:

arterial p02 (P) = 90

fraction percent of inspired oxygen (FI02) = .70

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

PFR = P/F = ?