PaO2/FiO2 ratio
Calculate PaO2/FiO2 ratio instantly with the exact formula and a worked example. Free online calculator — no signup.
PaO2/FiO2 ratio
PaO2, mmHg
FiO2 (0-1)
P/F ratio
428.5714
P/F
429
ARDS
Norm
More about: PaO2/FiO2 ratio
What it calculates
The “PaO2/FiO2 ratio” calculator computes P/F ratio from 2 parameters: pao2, mmhg, fio2 (0-1).
Used by professionals and patients to assess health metrics, dosages, and risks.
Example calculation
With parameters PaO2, mmHg = 90, FiO2 (0-1) = 0.21 the result is 428.57.
How to use
- Enter the parameter values — every field above is adjustable with a slider.
- The result and related metrics are calculated automatically as you type.
- Use the additional metrics shown (if any) where needed.
- Copy the result or bookmark the page.
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FAQ
How is BMI calculated?
BMI = weight (kg) / height (m)². Example: 70 kg / (1.75 m)² = 22.9. The WHO normal range is 18.5–24.9; below that is underweight, 25–29.9 is overweight, and 30+ is obese.
Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so athletes may show a high BMI with low body fat. It is also less reliable for teenagers, pregnant people, older adults, and very tall or short individuals.
What are the BMI categories?
Underweight: below 18.5. Normal: 18.5–24.9. Overweight: 25–29.9. Obese class I: 30–34.9; class II: 35–39.9; class III: 40+.
What is a better measure than BMI?
Body fat percentage, waist-to-height ratio (aim for under 0.5), and waist circumference give a clearer picture of health than BMI alone.