P/F Ratio Calculator

This calculator divides the arterial oxygen tension by the inspired oxygen fraction and reads the result against the Berlin definition bands. Enter PaO2 in mmHg or kPa, FiO2 as a percentage or a fraction, and optionally the barometric pressure and the PEEP, and it returns the ratio, the ratio after the altitude correction of pressure over 760, and which of the mild, moderate and severe bands it falls in. It also says whether the PEEP reaches the 5 cmH2O the definition requires before those bands apply. The ratio is only one of the four Berlin criteria, and the other three are matters of timing, imaging and clinical judgement that no calculator can settle. Nothing here is treatment advice.