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Oxygen Requirement At Altitude Calculator

Work out oxygen requirement at altitude instantly with clear inputs, formula shown and shareable results.

About Oxygen Requirement At Altitude Calculator

Supplemental oxygen quantity is flow rate per person multiplied by occupants and duration. The required inspired oxygen fraction is the fraction that restores sea-level partial pressure of oxygen at the cabin altitude, which is why around 34,000 ft demands essentially 100% oxygen and above that a pressure-demand system.

Formula

Oxygen quantity

Total = flow per person x occupants x minutes; required O2 fraction = 0.2095 x P(sea level) / P(altitude)

Worked example

With the default values below, Oxygen Requirement At Altitude Calculator returns Oxygen required of 630.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cabin altitude
25,000 ft
Occupants needing oxygen
6 people
Duration required
30 min
Flow per person at 25,000 ft
3.5 L/min

Results

Oxygen required
630.00 L
Flow per person
3.50 L/min
Inspired oxygen needed
56.5% %
Oxygen per person
105.00 L

Step by step

  1. 1Values used
  2. 2Oxygen quantity
  3. 3Oxygen required= 630.00 L
  4. 4Flow per person= 3.50 L/min
  5. 5Inspired oxygen needed= 56.5 %
  6. 6Oxygen per person= 105.00 L

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

Frequently Asked Questions

When is supplemental oxygen legally required?

Rules vary, but a common structure is crew oxygen above 10,000-12,500 ft cabin altitude for extended periods and passenger oxygen available above 15,000 ft. Check the applicable regulation.

Why is 100% oxygen not enough above 40,000 ft?

Even breathing pure oxygen the ambient pressure is too low to load the blood adequately, so pressure-demand equipment or a pressurised cabin is required.

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