Measure blood oxygen levels on Apple Watch

The Blood Oxygen screen taking a measurement while counting down.

Use the Blood Oxygen app on supported Apple Watch models to measure the percentage of oxygen your red blood cells carry from your lungs to the rest of the body. Knowing how well oxygenated your blood is can help you understand your overall health and wellness.

Note: Blood Oxygen app measurements are not intended for medical use. The ability to measure blood oxygen is no longer available on Apple Watch units sold by Apple in the United States on or after January 18, 2024. These units are indicated with part numbers ending in LW/A. Learn how to identify your Apple Watch.

What you need

Make sure the Blood Oxygen app is available in your country or region.
Update your iPhone XS or later to the latest version of iOS.
Update your supported Apple Watch to the latest version of watchOS.

Note: The Blood Oxygen app is not available for use by people under 18 years old. You can confirm or set up your age in your Medical ID.

Set up Blood Oxygen

Go to the Settings app on your Apple Watch.
Tap Blood Oxygen, then turn on Blood Oxygen Measurements.

Measure your blood oxygen level

The Blood Oxygen app periodically measures your blood oxygen level throughout the day if background measurements are turned on, but you can also take an on-demand measurement at any time.

Go to the Blood Oxygen app on your Apple Watch.
Rest your arm on a table or in your lap, and make sure your wrist is flat, with the Apple Watch display facing up.
Tap Start, then hold your arm very still during the 15-second countdown.
At the end of the measurement, you receive the results. Tap Done.

Note: To get the best results, the back of your Apple Watch needs skin contact. Wearing your Apple Watch not too tight or too loose, with room for your skin to breathe, and flush with the top of your wrist, helps ensure successful Blood Oxygen measurements. For more information, see the Apple Support article How to use the Blood Oxygen app on Apple Watch.

Turn off background measurements when the Sleep Focus or Theater Mode is active

Blood oxygen measurements use a bright red light that shines against your wrist, which may be more visible in dark places. You can turn off measurements if you find the light distracting.

Go to the Settings app on your Apple Watch.
Tap Blood Oxygen, then turn off In Sleep Focus and In Theater Mode.

View your Blood Oxygen measurements history

Go to the Health app on your iPhone.
Tap Browse, tap Respiratory, then tap Blood Oxygen.

Helpful?

Apple Watch User Guide