Apple Watch Sleep Score explained: how it works

How the points add up

Apple splits the 100 points like this:

Sleep duration, up to 50 points: how long you slept.
Bedtime consistency, up to 30 points: when you fell asleep, compared with the last 13 nights.
Interruptions, up to 20 points: how often you woke and how long you stayed awake.

Duration is half the score, so a short night pulls it down more than anything else.

What the bands mean

Apple gives every score a label:

Very low: 0 to 40
Low: 41 to 60
OK: 61 to 80
High: 81 to 95
Very high: 96 and above

These are Apple’s labels for your night, not medical categories.

Why your score might be lower than you expected

Look at which part lost points. A short night costs the most, because duration is worth up to 50 points. Falling asleep at a different time from usual lowers bedtime consistency, which looks back over your last 13 nights, so an uneven week can hold the score down even after a good night. Waking often, or lying awake for a while, lowers interruptions.

Fit and battery matter too. Apple advises wearing the watch at a comfortable fit, because a watch that’s too loose can register too much movement. It also says to charge it before bed, because it cannot track sleep if the battery runs out.

Where to find it

On Apple Watch, open the Sleep app. Turn the Digital Crown to see recent nights. On iPhone, open the Health app, tap Browse, then Sleep. Tap the score, then the info button, to see how that night’s points were worked out.

If you don’t get a score

Check that Track Sleep with Apple Watch is turned on, and that you wore the watch to bed. Apple says you need to wear it for at least an hour each night to get sleep data. How does Apple Watch track sleep? covers setting it up.

Sleep Score and Readiness

On Apple Watch Series 12 and Ultra 4, your recent Sleep Score is one of the three inputs to Apple’s Readiness score. A low sleep score can lower readiness, and a higher or improving one can raise it. Which Apple Watches get a readiness score? explains which models have it.

How much sleep you need

The NHS says adults need 7 to 9 hours. How much sleep do I need? goes into the detail, and the bedtime calculator works back from when you need to wake.

In Vital

Vital reads your sleep from Apple Health with your permission. Its Sleep page shows last night against the sleep you need, with your trend over 7, 30 and 60 days, and last night’s sleep is one of the readings behind your daily Readiness score. It works with or without an Apple Watch.

Get Vital for iPhone

Common questions

What is a good Apple Watch sleep score?

Apple labels 81 to 95 as High and 96 and above as Very high. There is no medical cut-off. Your own trend over a few weeks tells you more than a single night.

How is the Apple Watch sleep score calculated?

From sleep duration (up to 50 points), bedtime consistency over the last 13 nights (up to 30 points) and interruptions (up to 20 points), for a total out of 100.

Why is my Apple Watch sleep score low?

Usually a short night, a bedtime that differs from your recent nights, or time awake in the night. Tap the info button in the Sleep app, or the score and then the info button in the Health app, to see which part lost points.

Does sleep score affect Apple’s Readiness score?

Yes, on Apple Watch Series 12 and Ultra 4. Apple uses your recent sleep score as one of the three inputs, with activity and vitals.

Is the Apple Watch sleep score accurate?

It is an estimate. Apple Watch works out sleep from your wrist, and Apple says the watch is not a medical device. Read it over a week or more rather than night by night. If poor sleep is affecting your daily life, the NHS suggests seeing a GP.

Vital gives general information about fitness and wellbeing. It is not medical advice, and it does not diagnose or treat any condition.

How does the Apple Watch Sleep Score work?