Not All Sleep Quality Indicators Are Created Equal.

Sleep quality scores are perhaps one of the most frequently tested metrics in wearable health tracking devices, but there’s still no consensus among manufacturers. A Garmin user with a score of 75 receives a “Fair” rating. An Oura user with a score of 75 receives a “Good” rating. An Apple Watch user with a score of 75 might see a “Normal” or “Excellent” rating, depending on the software version. Where do these numbers come from, and what do they actually mean?

Each platform uses different scales, labels, and baseline cues to generate a unified morning score. Here’s how the most popular wearables calculate your “sleep score” and what it means for you.

What does your “sleep quality score” really mean?

When using all the scoring systems described below, it’s important to remember that a truly “accurate” sleep quality assessment is impossible. Your device tracks how long you apparently slept and makes assumptions about how much of that time was spent in light sleep, deep sleep, and rapid eye movement (REM) sleep. It then condenses this into a single aggregate score, which is perhaps more a product of branding decisions than clinical research.

So, while the data used to calculate your score (such as heart rate) may be accurate, it’s important to understand that the score itself is a fictional number. Ideally, sleep tracking works less like a medical test you pass or fail, and more as a way to identify patterns over time.

How the Oura Ring Calculates Your Sleep Quality Score

Let’s start with Oura, as it’s widely considered the best sleep tracker on the market.Oura’s sleep quality score ranges from 0 to 100, with three main rating zones:

• 85–100: Optimal . A score of 85 or higher means all your metrics are looking pretty good. Oura even marks this day with a crown icon in the app.

• 70–84: Good . Your sleep was good, but not excellent. You were well-rested and ready for most daily activities, but your sleep quality could still be improved.

• Readings below 70: Please note : Results below 70 indicate that you may benefit from prioritizing rest and recovery.

According to Oura, your sleep quality score is based on seven factors: total sleep time, sleep efficiency (the percentage of time actually spent asleep), restfulness, REM sleep, deep sleep, sleep latency (the time it takes to fall asleep), and sleep onset time (whether your sleep is in line with your body’s natural circadian rhythm).

Oura is the most accurate of all the wearables on this list, the study found, largely because it reads data from your finger, which provides a stronger optical signal than the wrist.

It’s important to note: scores of 100 are considered rare, not regular. Never scoring 85 is also not uncommon. Sleep naturally fluctuates, and there may be periods when your sleep is better or worse. Again, it’s more useful to focus on your sleep patterns over time than on the results of one particular night.

How Whoop calculates your sleep quality score

The Whoop app provides two metrics— a sleep quality percentage and a recovery score—and expects you to read them simultaneously.

The sleep quality score is expressed as a percentage from 0 to 100% and measures how much sleep your body actually gets. It’s calculated based on sleep adequacy (the percentage of sleep you actually need), sleep stability (the ratio between bedtime and sleep over the previous four nights), sleep efficiency (the percentage of time spent in bed actually sleeping), and sleep stress (the time spent in a physiologically high stress state during the night).

Recovery is a more general indicator of daily fitness, also expressed as a percentage, and it’s the metric most Whoop users check first. Recovery is divided into three color-coded zones: green (67–100%) means you’re well-rested and ready to work; yellow (34–66%) means your body is maintaining a normal activity level and is ready for moderate exercise; and red (0–33%) indicates your body likely needs some rest.

Whoop claims to compare your performance to your own baseline, not a fixed population standard, meaning your 70% recovery rate and your friend’s 70% recovery rate may reflect completely different conditions.

Whoop also stands out because it doesn’t provide a single “good/bad” verdict. The sleep quality percentage shows the quantity and consistency of your sleep relative to your personal needs, while the recovery score reflects your body’s response. Most people consider Whoop and Oura to be virtually equal among the best sleep trackers .

How a Garmin device calculates your sleep quality score

Now let’s move on to smartwatches. Garmin offers perhaps the most traditional rating system of all. Every morning, you receive a sleep quality score on a scale of 0 to 100, and based on this score, you’re assigned one of four ratings:

• 90–100: Excellent

• 80–89: Good

• 60–79: Satisfactory

• Under 60: Bad position

Garmin calculates its sleep quality score based on a combination of sleep duration, sleep quality, and “signs of restorative activity in the autonomic nervous system derived from heart rate variability data.” This last point means that Garmin tracks changes in the time between heartbeats during sleep and takes this into account when assessing overall sleep quality. Theoretically, this should account for, for example, the heightened state of the nervous system throughout the night, even if you’re physically motionless.

Garmin also has a Body Battery feature that shows how well your energy reserves have been replenished overnight. It’s calculated based on a combination of heart rate, heart rate variability (HRV), and movement data. When your sleep quality score is low, your Body Battery score tends to be low, too.

The Garmin (along with the rest of the smartwatches listed below) is best thought of as smartwatches that simply track sleep, rather than dedicated sleep tracking devices like the Oura or Whoop.

How Apple Watch calculates your sleep quality score

Apple’s sleep quality rating system is the latest addition to this list, coming in September 2025. But even with this latest update, Apple’s sleep quality ratings are considered too high.

Your score is calculated based on sleep duration (50 points), bedtime regularity (30 points), and interruptions—how often you wake up and how long you stay awake (20 points). The current five-point scale, updated in watchOS 26.2, looks like this:

• 96–100: Very High (previously called “Excellent,” but Apple renamed this category to better reflect the fact that it’s an objective rating, not a promise of how you’ll feel).

• 81–95: High

• 61–80: OK

• 41–60: Low

• 0–40: Very low

Compared to other trackers on this list, Apple’s score seems to be more focused on sleep habits (getting enough hours, a consistent sleep pattern, minimal waking) than on trying to identify sleep stages.

How Fitbit calculates your sleep quality score

Fitbit was one of the first mass-market wearables to introduce an official sleep score, and its system remains fairly simple and robust. Your overall sleep score is the sum of your sleep duration, sleep quality, and restorative scores, up to 100. Fitbit claims most people score between 72 and 83.

Four ranges:

• 90–100: Excellent

• 80–89: Good

• 60–79: Satisfactory

• Under 60: Bad position

Fitbit defines sleep duration as your total sleep time relative to your sleep goals; sleep quality evaluates how much time you spent in deep sleep and REM sleep; and recovery (the most distinguishing element) takes into account your heart rate while sleeping compared to your resting heart rate during the day, as well as how much time you spent tossing and turning. A higher recovery score is assigned when your heart rate while sleeping is significantly lower than your resting heart rate.

There’s one caveat: to see a detailed breakdown of your recovery score, you’ll need a Fitbit Premium subscription. Basic users see the overall score, but a detailed breakdown by component is only available for an additional fee.

What does a 75 rating mean on each platform?

Just for fun, let’s look at how different companies interpret the same number. Here’s what the number 75 might mean depending on your wearable device:

• Oura: I slept well and was well rested.

• Garmin: Satisfactory, meaning some things could be better.

• Apple Watch: Slightly above the middle of the pack with a “Fair” rating.

• Fitbit: Near the top end of the “Satisfactory” scale, below the “Good” threshold.

• WHOOP: Not exactly comparable since it’s based on percentages.

Result

None of the sleep quality metrics on these platforms are clinically accurate. They are rough estimates derived from wrist (or finger) sensors, algorithms built on population data, and proprietary definitions that neither company fully discloses. Two people who slept identically may receive different scores, and the same person may score 90 one night and 65 the next, with no apparent explanation.

Again, the most useful way to interpret these results is to identify trends over time, not to draw conclusions about sleep quality on a single night. To get the most out of your sleep analysis, I explain sleep tracking best practices here .

More…