What is a normal oxygen level?
Last updated September 3, 2026.
95 to 100 percent is normal on a pulse oximeter, per MedlinePlus - with asterisks: chronic lung disease can set a lower personal baseline, and altitude lowers everyone's. Act when readings drop below 92 percent, or when any low reading arrives with symptoms - breathlessness, chest pain, confusion, blue or grey lips - and severe symptoms mean 911 regardless of the number. Home-oximeter traps: nail polish blocks the sensor (use a bare finger), cold fingers read falsely low (warm first), movement scrambles readings, cheap devices vary - sit still, warm hand, bare nail, wait for steady. The rule that outranks the device: how you feel beats what it says. Pymander is a free AI doctor, 24/7 by text, and can help you judge a reading.
What to do
- Bare finger, warm hand, still: the accurate-reading recipe.
- Below 92 or falling with symptoms? Get seen now.
- Blue lips, gasping, confusion? 911 - no rechecking.
- Know your baseline if you have lung disease: your normal may differ.
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