It clips onto a fingertip and shines light through the skin to estimate how much oxygen your blood is carrying (SpO2), alongside your pulse rate. It's a quick, painless check that's useful for keeping an eye on a chest infection or a long-term lung condition at home — often at the suggestion of your GP or nurse.
Treatments & products
Oximeters — your questions, answered
How do I get an accurate reading?
Sit and rest for a few minutes first, warm your hands, and remove nail polish or false nails from the finger you're using. Keep your hand still, roughly at heart level, and wait for the number to settle — it can take a minute. If you're monitoring over time, take readings at the same times each day and write them down so you can spot a trend.
What's a normal oxygen level?
Most healthy people read between 95% and 100%. Some long-term lung conditions normally run lower — your GP or nurse will tell you what range to expect for you. If your reading is 92% or lower, or you feel increasingly breathless or unwell, get urgent medical advice — and always trust how you feel, not just the number.
Are pulse oximeters accurate on darker skin?
They can be less accurate on darker skin tones — readings may show slightly higher than the true level, something the UK medicines regulator (MHRA) has highlighted. The advice isn't to avoid using one, but to watch the trend in your readings over time rather than relying on any single number, and to get medical advice promptly if you feel unwell whatever the display shows.
Information only — always read the patient leaflet and ask our pharmacist if you're unsure. Prescription treatments are supplied only after a consultation and our pharmacist's approval.