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)

To calculate PF ratio, divide the arterial p02 by the fraction percent of inspired oxygen.

## 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