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PaO₂/FiO₂ Ratio (P/F Ratio) Calculator

P/F = PaO₂ / FiO₂ — Berlin ARDS severity grading.

Compute the PaO₂/FiO₂ (P/F) ratio used in the Berlin definition of ARDS: P/F = PaO₂ (mmHg) / FiO₂ (decimal, e.g. 0.40 for 40 %). Severity bands (with PEEP/CPAP ≥5): mild ≤300, moderate ≤200, severe ≤100.

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

Inputs

mmHg

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

P/F = PaO₂ / FiO₂.

In depth

Compute the PaO₂/FiO₂ (P/F) ratio used in the Berlin definition of ARDS: P/F = PaO₂ (mmHg) / FiO₂ (decimal, e.g. 0.40 for 40 %). Severity bands (with PEEP/CPAP ≥5): mild ≤300, moderate ≤200, severe ≤100.