Sleep score: what it measures, what makers publish and what a good score means

What is a sleep score?

A sleep score turns a night into one number from 0 to 100. The tracker records movement and heart signals, estimates when you slept and woke, then scores a handful of measures and adds them up. Oura and Garmin describe it as a 0 to 100 number, and Apple’s parts add up to 100 points.¹³⁴

The number is a product feature, not a medical standard. No government agency publishes a sleep score formula. What institutions do publish is how much sleep adults need and what good sleep looks like, and those facts are the only fixed points you can check a score against.⁵⁷

That is why two bands on one wrist can disagree. A night of 7 hours with three long awakenings can score well in one app and poorly in another, because each one weighs the parts differently.

What do the makers publish, and what do they keep private?

Every maker below was read on its own official page on October 16, 2026. The table lists what each page says about its score. A blank in the last column is not a criticism. It only records what the page does not disclose.

Three things stand out. First, all four count duration. Second, no two makers use the same list of parts: Apple scores bedtime consistency, Garmin scores overnight recovery from heart rate variability, and Oura scores stage minutes. Third, only Apple gives point values.¹³⁴

Fitbit and Garmin both say the targets depend on you. Google says the algorithm compares your data with targets adjusted for age, gender and time asleep or trying to sleep.² Garmin says duration is judged against age-based standards agreed upon by sleep experts, without printing them.³

How are the common parts measured?

Time asleep

Every score in the table counts it. Oura says most adults need 7 to 9 hours.¹ The CDC says adults aged 18 to 60 need 7 or more hours, and the NHLBI says experts recommend 7 to 9 hours for adults.⁵⁷ If a tracker says you slept 6 hours 30 minutes, that is the number to trust most. Chinoy and colleagues tested seven consumer devices against a sleep lab and found high performance at detecting sleep.⁶

Efficiency

Oura defines sleep efficiency as the share of time in bed spent asleep, and its page names 85% as a sign of peaceful, uninterrupted sleep.¹ The arithmetic is simple, as the worked example further down shows.

Awakenings and restlessness

Fitbit separates brief stirs, under five minutes, from full awakenings, longer than five minutes. Google says zero full awakenings is ideal and fewer than two is considered good for most people.² Apple scores interruptions as how often you wake and how long you stay awake.⁴

Stage minutes

Oura scores REM and deep sleep. Its page gives about 1.5 hours of REM as optimal for most healthy adults, and an average of 15% to 20% of the night, about 1 to 1.5 hours, for deep sleep.¹ Stage labels from a wrist device are estimates. In the lab comparison above, stage assessments were inconsistent between devices, and the devices did worse on nights of disrupted sleep.⁶ For what stages are, see the guide to sleep stages.

Timing and consistency

Apple gives 30 of 100 points to bedtime consistency over the last 13 nights.⁴ Oura scores timing against your body clock and says the midpoint of sleep should ideally fall between midnight and 3 a.m., depending on your chronotype.¹ The NHLBI also advises a steady wake time, with no more than about an hour of drift between weeknights and weekends.⁸

Heart rate and recovery

Fitbit counts a lower sleeping heart rate than daytime resting rate toward restoration, and Garmin draws its recovery part from heart rate variability.²³ These signals are the link between sleep and the readiness scores some bands show. The readiness score guide covers that side, and the HRV guide explains the signal itself.

Worked example: efficiency and the Apple points

Say you are in bed from 11:00 p.m. to 7:00 a.m. That is 8 hours, or 480 minutes. Your tracker says you slept 6 hours 45 minutes, or 405 minutes.

Notice what the example shows. Efficiency of 84.4% sits a hair under 85%, so a small change in how long you took to fall asleep moves it across the line. A score that drops a few points on a night like this is telling you about minutes, not about a problem.

For Apple, the same night would have its duration judged out of 50 points, its interruptions out of 20 and its timing out of 30. The page does not print the curve that converts 405 minutes into duration points, so the arithmetic stops there.⁴

What does a good sleep score mean?

Each maker defines good differently, so a good score only makes sense inside its own app. Oura calls 70 to 84 good, Fitbit calls 80 to 89 good and Apple calls 81 to 95 high.¹²⁴ The same night could land in different bands in different apps.

Google adds a useful anchor: most Fitbit users see an average score between 72 and 83.² That means a score in the high 70s is an ordinary night for that app, not a failure.

What a good score does not tell you

A score cannot tell you why you slept the way you did, and it cannot judge your health. The NHLBI describes sleep deficiency as getting too little sleep, sleeping at the wrong time, sleeping poorly, or having a sleep disorder that prevents enough sleep.⁹ A tracker can hint at the first three. It cannot rule on the fourth.

A high score can also hide a problem if you feel unrested. The CDC says quality sleep means uninterrupted, refreshing sleep, and that how you feel after sleep matters as much as the hours.⁵ If your score is fine but you are tired for weeks, talk to a clinician.

How to improve a sleep score without chasing it

Chasing a number can backfire, since worry about sleep makes sleep harder. The habits below are the ones the CDC and NHLBI recommend for sleep itself. Any score tends to follow.

• Go to bed and get up at the same time every day, which feeds the timing and consistency parts.⁵
• Keep the bedroom quiet, relaxing and cool, and put electronics away at least 30 minutes before bed.⁵
• Avoid large meals, alcohol and late caffeine. The NHLBI says caffeine can last up to 8 hours.⁸
• Get daylight and be active during the day.⁸

The full list is in the guide to how to improve sleep quality. If your numbers show a gap against your target, sleep debt explains how the gap builds and how slowly it clears. To see how much sleep each age group needs, read how much sleep you need.

Choosing a tracker for sleep trends

If you want a sleep score, look for a maker that shows the parts of the score, states its bands and lets you export the nights. If you only want trends, any device that records sleep time, heart rate and heart rate variability steadily will do. The best sleep trackers comparison sets devices side by side with dated sources.

Whatever you pick, wear it the same way every night. Changes in a device’s position or software update can move a score without any change in your sleep.

Frequently asked questions