Advanced Oxygen Saturation Calculator

For healthy adults at sea level, normal SpO2 is 95-100%. Levels of 91-94% indicate mild hypoxemia. Below 90% is concerning and requires medical attention. Below 85% is a medical emergency. Note: Normal ranges are lower at high altitudes.

At higher altitudes, atmospheric pressure is lower, making oxygen absorption less efficient. Normal SpO2 at sea level (95%+) drops to about: 94% at 1000m, 92% at 3000m, 88% at 5000m. This is physiological adaptation, not hypoxemia. Our calculator adjusts for altitude.

SpO2 below 90% is considered hypoxemia and may require supplemental oxygen. Below 85% is severe hypoxemia—immediate medical attention needed. Below 80% is life-threatening. Cyanosis (blue lips/fingers) often appears around 85% or lower.

Low oxygen symptoms: Mild (headache, fatigue, restlessness). Moderate (shortness of breath, rapid breathing, rapid heart rate, confusion). Severe (blue lips/fingertips, extreme confusion, inability to speak, chest pain). Symptoms can develop gradually or rapidly.

FDA-approved pulse oximeters are typically accurate within ±2% for readings above 70%. Accuracy decreases with: poor circulation, cold fingers, nail polish, dark skin tones (FDA has noted potential inaccuracies), movement, or very low readings. For critical decisions, arterial blood gas testing is more accurate.

Supplemental oxygen is typically prescribed when SpO2 falls below 88-90% at rest or during sleep. Common conditions: COPD, severe asthma, pneumonia, COVID-19, pulmonary fibrosis. Never self-prescribe oxygen—always follow medical guidance. Oxygen settings depend on individual needs.

Natural SpO2 cannot exceed 100%. However, patients on supplemental oxygen can maintain 100% when less might be needed. Oxygen toxicity (from excessive supplemental O2) is a concern in medical settings. For COPD patients, target is often 88-92% rather than 100%.

SpO2 (peripheral oxygen saturation) is the percentage of hemoglobin carrying oxygen—measured non-invasively by pulse oximeter. PaO2 (partial pressure of arterial oxygen) is the amount of dissolved oxygen in blood—measured via arterial blood gas. SpO2 of 95% roughly equals PaO2 of 80-100 mmHg.

COVID-19 can cause 'silent hypoxia'—dangerously low oxygen without feeling breathless. Some patients have SpO2 in the 80s without realizing it. Recommendations: Monitor SpO2 regularly if COVID-positive. Seek care if below 94% or dropping. Hospitalization often recommended below 92%.

COPD damages lung tissue, reducing oxygen transfer efficiency. Many COPD patients have baseline SpO2 of 88-92%. Their target is often 88-92% (not 95%+) because: they've adapted to lower levels, and too much oxygen can suppress their breathing drive. Always follow individual medical guidance.

Cyanosis is bluish discoloration of skin/lips due to low oxygen in blood. Central cyanosis (lips, tongue) indicates severe hypoxemia (SpO2 typically below 85%). Peripheral cyanosis (fingertips) can occur with cold or poor circulation. Cyanosis in babies, children requires immediate medical attention.

For healthy people: Occasional checks are sufficient. For respiratory conditions (COPD, asthma): As recommended by doctor, often 2-3 times daily. During illness (COVID, pneumonia): Every 4-6 hours while awake. If on oxygen therapy: Per medical guidance, often before and after activity.

Anxiety itself doesn't lower actual oxygen levels—it may even cause hyperventilation (higher O2). However, anxiety can affect readings: shaking/movement reduces accuracy, cold hands from stress affect signal, and panic can make you perceive breathlessness without actual hypoxemia. True hypoxemia has physical signs beyond just feeling breathless.

Oxygen therapy provides supplemental oxygen to raise blood oxygen levels. Methods: Nasal cannula (1-6 L/min), simple mask (5-10 L/min), non-rebreather mask (10-15 L/min), high-flow nasal cannula (up to 60 L/min), mechanical ventilation. The goal is to maintain SpO2 at target level (typically 92-96%).

Call 911 immediately if: SpO2 below 85% (at sea level), blue lips/fingertips/face, severe difficulty breathing or inability to speak full sentences, confusion or altered consciousness, chest pain with low SpO2, rapid decline in SpO2 despite rest. Don't wait—hypoxemia can rapidly become life-threatening.