How-to guide · Fingertip pulse oximeters
Blood oxygen saturation: what SpO₂ means
SpO₂ estimates how much of the hemoglobin in your blood is carrying oxygen. When you interpret the number, consider how you took the reading, how you feel, and the limitations of your pulse oximeter.
What blood oxygen readings are typical?
The FDA puts the range for most healthy people at 95% to 100%. A person’s usual level may be lower at higher elevations or with certain lung or heart conditions. If your health care provider asked you to check your oxygen at home, follow the range and instructions they gave you.
Each reading is an estimate for that moment. Note whether you were resting or had just exercised, and compare readings taken under similar conditions. Get immediate help for severe symptoms even if the device shows a number in your usual range.
How to read oxygen saturation and pulse rate
| Indicator | What it shows |
|---|---|
| SpO₂ | Estimated peripheral oxygen saturation, shown as a percentage. |
| PR or bpm | Pulse rate, in beats per minute. |
| PI, when displayed | Information about the pulsing signal where the sensor sits. See our guide to perfusion index. |
On a small display, look at the unit and label next to each number. If the screen rotates or the reading fluctuates when you put on the clip, see our step-by-step guide to using a pulse oximeter.
What can affect a reading?
The FDA lists factors including circulation, skin temperature, skin thickness, skin pigmentation, tobacco use, and nail polish. If the number changes as you move, follow your device’s instructions, keep your hand still, and wait for the display to settle.
If a reading concerns you, contact your health care provider. General wellness products and medical devices have different intended uses. Check the documentation for the exact model before choosing one.
Blood oxygen and pulse log
Write down the date, time, and how you felt next to the SpO₂ and pulse readings. If you took a second reading, record it along with any change in conditions. Bring the log to your appointment if your health care provider asked you to monitor at home.
What to check when choosing a pulse oximeter
Check the device’s intended use, fit, and which readings you can see or save. Our fingertip pulse oximeter comparison explains those differences for US models. You can also check the Beurer PO50 product guide.