How to use the alveolar oxygen pressure calculator
Estimate the oxygen pressure in the lungs air sacs using the alveolar gas equation. Enter inspired oxygen fraction, atmospheric pressure, arterial co₂ pressure in the fields above; the alveolar oxygen pressure is computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “alveolar gas equation”, “PAO2”, “lung oxygen pressure”, “calculate alveolar oxygen pressure”, “find alveolar oxygen pressure”.
Formula
Variables
- fio2 — Inspired oxygen fraction
- patm — Atmospheric pressure (mmHg)
- paco2 — Arterial CO₂ pressure (mmHg)
Worked example
With inspired oxygen fraction = 0.21, atmospheric pressure = 760 mmHg, arterial co₂ pressure = 40 mmHg, the calculator gives alveolar oxygen pressure ≈ 99.73 mmHg.
Frequently asked questions
What is the alveolar oxygen pressure calculator used for?
Estimate the oxygen pressure in the lungs air sacs using the alveolar gas equation. It helps with questions such as “alveolar gas equation”, “PAO2”, “lung oxygen pressure”.
What is the formula for the alveolar oxygen pressure calculation?
Alveolar oxygen pressure (mmHg) = fio2 × (patm-47)-paco2 / 0.8. Here fio2 is inspired oxygen fraction, patm is atmospheric pressure (mmHg), paco2 is arterial co₂ pressure (mmHg).
What inputs do I need for the alveolar oxygen pressure calculator?
You need inspired oxygen fraction, atmospheric pressure in mmHg, arterial co₂ pressure in mmHg. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the alveolar oxygen pressure calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the alveolar oxygen pressure result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.