Type the oxygen number from your pulse oximeter — the one marked SpO2 or %. You get what that number means against the published lines, and the range the device’s own error puts around it.
An adult reading of 96%
96% — in the range most healthy people readThe FDA puts most healthy people between 95% and 100%.
| Age | People | Middle half read | Typical (median) |
|---|
This is a way to read a number against published guidance, not a diagnosis. If you feel unwell, or a reading worries you, contact your doctor or the emergency services rather than re-testing until you get a number you like.
Thresholds and sources checked 2026-09-22.
Quick answer: the FDA puts most healthy people between 95% and 100%. NHS England’s home guidance says phone your GP or NHS 111 at 93 or 94%, and at 92% or less check again straight away and, if it stays there, go to A&E or call 999 (in the US, 911). But the number on the screen is not the whole answer: the FDA’s own figure, as NIH reports it, is that a cleared oximeter reading 90% means your blood is generally somewhere between 86% and 94% — so a reading can sit on the wrong side of a line by the device’s error alone.
How to use it
Type the oxygen number from your oximeter — the one marked SpO2 or with a % sign, not the pulse. Then tell it whose reading it is, whether a doctor has given you a lower 88–92% target, what took the reading, and whether you live high up. The answer comes first, the device’s error band is drawn around your number, and every line on the drawing is labelled with who published it.
If the reading is low enough for any published guidance to say act now, that advice is printed at the top, above everything else.
The part other charts leave out: how much of the number is the device
Every chart of “normal oxygen levels” prints 95–100% and stops. What it does not print is that the gadget on your finger is allowed to be a few points out. The FDA asks makers of clip-on fingertip oximeters to show an accuracy (Arms) of 3 points or better against arterial blood, tested between 70% and 100%, and its plain-language summary is wider still: a cleared oximeter reading 90% means the real figure is generally between 86% and 94%.
That matters most exactly where the decisions are. A reading of 94% could be anything from 90% to 98% — which spans “fine”, “phone today” and “go now”. That is why this checker draws the band and says which lines it crosses, and why the NHS tells you to take a second reading before acting on a low one.
And some devices have no published accuracy at all. An oximeter sold for sports, aviation or “wellness”, and the blood-oxygen reading on a watch or ring, is not reviewed by the FDA before it goes on sale. There is no honest band to draw around its number, so the checker does not draw one.
What can make a reading wrong
The FDA lists poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use and fingernail polish. Two of those deserve more than a line:
- Cold hands. A cold finger has less blood flowing through it, and the oximeter can read wrongly or not at all. Warm your hands first — the NHS says rest the hand for five minutes before you measure.
- Darker skin. A 2020 study in the New England Journal of Medicine looked at hospital patients whose oximeter read 92–96% and checked their arterial blood. The blood was actually below 88% in about 12 of every 100 measurements in Black patients, against 4 in White patients, at one hospital — and 17 against 6 across 178 hospitals. The error runs in the dangerous direction: the screen says fine when the blood is not.
If a doctor gave you a target of 88–92%
For people at risk of carbon-dioxide retention — most often with COPD — the British Thoracic Society suggests a target of 88–92% instead of the usual higher range. For them, 90% is where they are meant to be, and a reading well above 92% on prescribed oxygen can be a problem too. Choose that option only if a clinician gave you that target; the general NHS lines then stop applying and your own care plan takes over.
Worked examples
97% on a cleared fingertip oximeter, adult. Inside the 95–100% the FDA gives for most healthy people. The device’s band runs from 93% to 100%, which crosses the 94% line, so if you feel unwell, take it again rather than trusting one good number.
94%, same device. NHS England says phone your GP or NHS 111. The band runs 90–98%, crossing both NHS lines — the real figure could be comfortably normal or in the act-now range, which is exactly why a person should look at you rather than a screen.
90% with a doctor-given 88–92% target. Inside the target. Nothing in the general NHS lines applies to you; your care plan does.
93% on a smartwatch. No published accuracy, no band. Check it on an FDA-cleared fingertip oximeter before acting on it either way.
Oxygen levels by age
The British Thoracic Society says normal daytime saturation is 96–98% in young adults, sitting down at sea level, and that the lower limit falls with age to about 94% in people over 70. The table under the checker shows the largest dataset the Society prints: 37,299 adults measured on arrival at four UK acute medical units, breathing air. They were hospital patients, not a healthy sample, and the table is labelled that way — but it shows the direction clearly. The typical reading is 98% at 18–24 and 96% at 65 and over.
For children, the published home thresholds on this page do not apply — the BTS guideline itself covers people over 16 only. The number to watch for a child is the one their own doctor, nurse or NHS 111 gives you.
FAQ
What is a normal oxygen level?
What oxygen level is too low?
Is 94 a good oxygen level?
Is 95 oxygen level good?
What is a normal oxygen level for someone with COPD?
How accurate are fingertip pulse oximeters?
Do pulse oximeters work on dark skin?
Is my Apple Watch or smart ring blood oxygen accurate?
More from the site
Read more on what a normal blood oxygen level is at each age, the pulse oximeter readings chart explained, how accurate finger pulse oximeters are, choosing an oximeter for darker skin and which pulse oximeters are FDA-cleared.