P/F Ratio Calculator (PaO₂/FiO₂)
The oxygenation index that defines ARDS severity — with the FiO₂ decimal trap handled.
A healthy P/F runs ~400–500 (PaO₂ 95 on room air 0.21 ≈ 452). The ratio normalises oxygenation across oxygen doses — 80 on 40% is a very different lung from 80 on room air. Berlin criteria also require PEEP ≥5, timing and imaging; the SpO₂/FiO₂ ratio (×~1.2 correlation) substitutes where no arterial line exists.
Formula
Reference aid for healthcare professionals only. Every result must be independently verified before clinical use. Never use this tool for self-medication or to replace clinical judgement.
The oxygenation index that defines ARDS severity — with the FiO₂ decimal trap handled. The P/F Ratio Calculator (PaO₂/FiO₂) is a free, private pf ratio tool — every result computes instantly in your browser with no sign-up and no data upload.
About P/F Ratio Calculator (PaO₂/FiO₂)
A healthy P/F runs ~400–500 (PaO₂ 95 on room air 0.21 ≈ 452). It applies P/F = PaO₂ ÷ FiO₂ (FiO₂ as a decimal: 40% = 0.40). Use the P/F Ratio Calculator (PaO₂/FiO₂) to get an instant, clearly-explained result with the working shown step by step — free, private and with the source method cited.
How to use P/F Ratio Calculator (PaO₂/FiO₂)
- 1Enter your details in the P/F Ratio Calculator (PaO₂/FiO₂) input fields above.
- 2The result updates instantly with the working and reference bands shown.
- 3Adjust any value to explore how it changes the outcome — it's free and unlimited.
Why use P/F Ratio Calculator (PaO₂/FiO₂)?
- ✓Instant pf ratio result that recomputes as you type — no waiting, no page reloads
- ✓100% client-side: your health data never leaves your browser
- ✓Shows the actual formula and your numbers substituted in, so you can see exactly how the result is reached
- ✓Based on published, citable sources (ARDS Definition Task Force, JAMA 2012 — Berlin definition)
- ✓Free forever with no sign-up, account or app install
Frequently asked questions
How does the P/F Ratio Calculator (PaO₂/FiO₂) work?+
A healthy P/F runs ~400–500 (PaO₂ 95 on room air 0.21 ≈ 452). The calculation uses the formula: P/F = PaO₂ ÷ FiO₂ (FiO₂ as a decimal: 40% = 0.40). Everything runs instantly in your browser as you type — your inputs are never uploaded.
Is the P/F Ratio Calculator (PaO₂/FiO₂) accurate, and what is it based on?+
The method is traceable to authoritative sources: ARDS Definition Task Force, JAMA 2012 — Berlin definition. Results are estimates — individual variation always applies, so treat the output as a well-grounded starting point.
Is the P/F Ratio Calculator (PaO₂/FiO₂) free and private?+
Yes. It's completely free with no sign-up, and all computation happens locally in your browser, so none of your health data ever leaves your device.
Can I use this for medical decisions?+
This is a reference aid for healthcare professionals and must be independently verified. It is not for self-diagnosis or self-medication.
What can I use the P/F Ratio Calculator (PaO₂/FiO₂) for?+
It's commonly used for pf ratio, pao2 fio2, ards criteria. The oxygenation index that defines ARDS severity — with the FiO₂ decimal trap handled.
Related Health tools
Adult BMI Calculator (WHO)
Body-mass index for adults with the WHO reference bands shown neutrally, plus the substituted formula step by step.
● LiveBMI Calculator (lb & inches)
US-style BMI from pounds and inches using the ×703 conversion, with CDC adult reference ranges.
● LiveBMI Calculator for Women
BMI with reference context written for women — what the index can and cannot say about female body composition.
● Live