Enter your altitude (and optionally your body temperature) to estimate a typical oxygen saturation (SpO2) at altitude. Altitude is the primary driver; for most users, assuming ~37 °C is reasonable.

Oxygen Saturation At Altitude Calculator

Main Calculator
Expected SpO2 by Altitude

Enter altitude to estimate a typical SpO2 for a healthy adult at rest. Body temperature has a smaller modeled effect; if left blank, 37 °C is assumed. You may optionally enter a measured SpO2 to compare it with the model estimate.

Important: This calculator provides an educational estimate and cannot diagnose or rule out hypoxemia, altitude illness, pneumonia, COVID-19, or other conditions. If your SpO2 is unexpectedly low or rapidly falling, or you have severe symptoms (trouble breathing, chest pain, confusion, bluish lips/face), seek urgent medical care/emergency services. Pulse oximeters can be inaccurate in some situations (poor circulation, movement, nail polish, and known accuracy limitations across different skin tones), and carbon monoxide poisoning may show falsely normal SpO2.

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Related Calculators

Oxygen Saturation At Altitude Formula

The calculator above uses a simplified physiology-based model to estimate oxygen saturation (SpO2) from altitude and body temperature. This is not an exact clinical calculation.

Method note: For background on the standard-atmosphere pressure relationship, the alveolar gas equation, and oxygen–hemoglobin dissociation curve approximations, consult standard physiology/respiratory medicine references and reputable public-health/medical education sources (e.g., NIH/CDC-style guidance pages). Last reviewed: 2026-01-01.

Model (summary)
1) Barometric pressure (standard atmosphere):
Pb = 760 × (1 – 2.25577×10-5 × Altitude)5.25588 (mmHg)

2) Water vapor pressure at body temperature (Tetens approximation):
PH2O(T) ≈ 0.75006 × 6.1078 × 10(7.5T/(237.3+T)) (mmHg)

3) Simplified alveolar gas equation (assumes FiO2=0.2095, RQ=0.8, and a typical PaCO2 decrease with altitude):
PAO2 ≈ FiO2 × (Pb – PH2O) – PaCO2/RQ
PaCO2 ≈ clamp(20, 40 – 0.003×Altitude, 40) (mmHg)

4) Convert to an SpO2 estimate using an approximate oxygen–hemoglobin dissociation curve (Severinghaus-style approximation):
PaO2 ≈ PAO2 – 5 (mmHg)
SpO2 ≈ 100 / (1 + 23400 / (PaO23 + 150×PaO2))

Variables:

  • SpO2 is the estimated oxygen saturation (pulse oximeter %) at altitude
  • Altitude is the altitude in meters
  • Temp is the body temperature in Celsius (°C)

To estimate SpO2 at altitude, the model first estimates barometric pressure from altitude, then estimates alveolar oxygen using a simplified alveolar gas equation, and finally converts the resulting oxygen pressure to an estimated saturation using an approximate oxygen–hemoglobin dissociation curve. Because ventilation (CO2), exertion, acclimatization, and medical conditions vary widely, treat the result as a rough estimate only.

What Is Oxygen Saturation at Altitude?

Oxygen saturation at altitude refers to the lower blood oxygen saturation (SpO2) that many people experience at higher elevations. The fraction of oxygen in air remains about 21%, but the barometric pressure drops with altitude, so the partial pressure of oxygen decreases. This can make it harder to maintain normal blood oxygen levels and can contribute to hypoxia. Symptoms may include shortness of breath (especially with exertion), faster heart rate, headache, dizziness, and impaired coordination.

How to Calculate Oxygen Saturation At Altitude?

The following steps outline how to estimate Oxygen Saturation at Altitude.

  1. First, determine the altitude in meters (Altitude).
  2. Next, determine the body temperature in Celsius (Temp).
  3. Next, use a model to estimate barometric pressure and then estimate PaO2 (oxygen pressure in blood) using the alveolar gas equation.
  4. Finally, convert the estimated PaO2 to an estimated Oxygen Saturation at Altitude (SpO2) using an oxygen–hemoglobin dissociation curve approximation.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Altitude = 2000 meters

Body Temp = 37 degrees Celsius

Estimated SpO2 ≈ 93% (healthy adult at rest; approximate)