Heart Rate (Resting)
60–100 beats per minute
Respiratory Rate (Resting)
12–20 breaths per minute
SpO₂ at Sea Level
95–100%
Sea Level
SpO₂: 95–100%
2,500m (8,200ft)
SpO₂: 90–95%
4,000m (13,100ft)
SpO₂: 85–90%
5,500m (18,000ft)
SpO₂: 80–85%
Blood oxygen saturation, measured as SpO₂ (peripheral capillary oxygen saturation), indicates the percentage of hemoglobin in your blood that is bound to oxygen. Hemoglobin is the protein in red blood cells responsible for carrying oxygen from your lungs to tissues throughout your body. A healthy SpO₂ level typically ranges from 95% to 100% at sea level, meaning that nearly all of your hemoglobin molecules are carrying oxygen.
SpO₂ is a vital sign that healthcare providers monitor to assess respiratory and cardiovascular function. Low oxygen saturation (hypoxemia) can indicate various conditions including respiratory disorders, heart problems, anemia, or altitude-related effects. Modern pulse oximeters measure SpO₂ non-invasively using light absorption through the fingertip or earlobe.
Several factors can influence your blood oxygen saturation levels. Understanding these factors helps interpret SpO₂ readings in the proper context and identify potential causes of low oxygen levels.
Altitude
At higher altitudes, atmospheric pressure decreases, reducing the amount of oxygen available for breathing. SpO₂ levels naturally decrease at altitude, with acclimatization occurring over days to weeks.
Physical Activity
During exercise, oxygen demand increases. While healthy individuals maintain normal SpO₂ during activity, those with respiratory or cardiovascular conditions may experience oxygen desaturation.
Respiratory Conditions
Conditions like COPD, asthma, pneumonia, and COVID-19 can impair gas exchange in the lungs, leading to lower oxygen saturation levels even at rest.
Age and Overall Health
Older adults may have slightly lower baseline SpO₂ levels. Cardiovascular health, anemia, and other systemic conditions can also affect oxygenation.
While this calculator provides estimates based on physiological parameters, actual SpO₂ should be measured with a pulse oximeter for accuracy. Seek medical attention if you experience:
- • Shortness of breath or difficulty breathing
- • Bluish discoloration of lips, face, or fingernails (cyanosis)
- • Chest pain or tightness
- • Confusion or altered mental status
- • Rapid or irregular heartbeat
- • Measured SpO₂ consistently below 92% at rest
Important Medical Disclaimer
SpO₂ estimates are for informational purposes only and may not reflect actual blood oxygen levels. This calculator cannot replace medical-grade pulse oximetry or clinical evaluation. Do not use this tool to diagnose or treat any medical condition. Consult a healthcare professional for accurate measurement and evaluation of your oxygen saturation, especially if you have symptoms of respiratory distress or cardiovascular issues.