Saturate · Apple Watch
The oxygen in the air around you.
As you climb, air pressure drops and every breath delivers less oxygen. Saturate reads your watch's barometer and shows the effective oxygen percentage — live, on your wrist.
How it works
Pressure in. Oxygen out.
Saturate measures your local air pressure and translates it into the sea-level oxygen concentration that matches what you're breathing now — about 20.9% at sea level, falling as you go higher.
The barometer
Series 3 and later carry a barometric altimeter. Saturate samples the air pressure right at your wrist.
To effective O₂
Lower pressure means thinner air. That pressure becomes an easy-to-read effective oxygen percentage, plus a “% of sea level” view.
Color by altitude
The ring is tinted by altitude band, from green at sea level to indigo in the death zone — readable at a glance.
When the barometer isn't available, Saturate falls back to GPS altitude. With Location enabled, it can also label a nearby place — handled by Apple's services, never sent to us.
Sea level to summit
Watch the air thin as you climb.
From the coast to 29,000 feet, the same six altitude bands the app uses — and roughly how much oxygen each breath delivers.
Effective-oxygen figures are approximate and for illustration. Saturate computes a live value from your actual measured pressure.
On your wrist
A whole climb, one glance at a time.
What you get
Everything, nothing more.
Effective oxygen %
The headline reading — color-coded by altitude band.
% of sea level
100% at sea level, dropping steadily as you ascend.
Live altitude scale
Sea level to 29,000 ft, with a marker for exactly where you are.
Altitude & pressure
Your current elevation and the air pressure behind the reading.
Watch complications
A rectangular overview plus focused Effective O₂ and % of Sea Level for circular, corner, and inline slots.
Six color zones
From Low to Ultra altitude — green through indigo, like the app icon's climb.
No account. No ads. No servers.
Readings are computed on your device. Saturate has no analytics and no third-party SDKs — nothing about you leaves your wrist. Privacy →
Not a medical device
Saturate measures the surrounding air — not your blood oxygen (SpO₂). It makes no medical claims. Always follow proper acclimatization guidance at altitude.
Almost here
Saturate is coming to the App Store.
Built for hikers, climbers, skiers, altitude training, and travelers heading somewhere high.