P/F Ratio — ARDS Severity Classification

Calculate the PaO2/FiO2 (P/F ratio) to classify ARDS severity: mild (200–300), moderate (100–200), and severe (<100 mmHg) according to the Berlin Definition, and guide ventilator management decisions.

Weight
Height
Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.
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How to Use

Enter the values for the scenario you are assessing. Calculate the PaO2/FiO2 (P/F ratio) to classify ARDS severity: mild (200–300), moderate (100–200), and severe (<100 mmHg) according to the Berlin Definition, and guide ventilator management decisions. Use the p/f ratio result to inform your calculation.

Frequently Asked Questions