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What sleep scores measure

What goes into the sleep and readiness scores from Oura, WHOOP, Apple Watch and Garmin, according to each company's own documentation.

Changes:

Short answer

Every sleep score mixes the same few things: how long you slept, how often you woke, how regular your timing was and, on some devices, your sleep stages and overnight heart data. Only Apple publishes its weighting (50% duration, 30% bedtime consistency, 20% interruptions). None of the four companies publishes its full formula, and no independent study has tested whether the scores themselves predict health.

Why it matters

A score is a summary. If you know what goes into yours, you know which habit can move it and which part is guesswork. Total sleep is the biggest input everywhere. Oura calls it the most significant contributor to its Sleep Score [1], and Apple gives it half the points [6].

This site is not affiliated with Oura, WHOOP, Apple or Garmin. Everything below comes from each company’s public pages, checked on 4 October 2026. Companies change their scores, so check your app’s help pages too.

How to do it

  1. Find your brand below and note which inputs it uses.
  2. Tap into the contributors in your app, not just the headline number. The contributor that’s low tells you what to work on.
  3. Compare weeks, not nights. Several inputs are already averages over 2 weeks or more.

Oura

  • Sleep Score bands: 85–100 Optimal, 70–84 Good, 60–69 Fair, 0–59 Pay attention [1].
  • Contributors: Total Sleep (most adults need 7–9 hours), Efficiency (85% is a sign of uninterrupted sleep), Restfulness, REM (about 1.5 hours), Deep Sleep (adults average 15–20% of sleep, 1–1.5 hours), Latency (ideally 15–20 minutes to fall asleep) and Timing (sleep midpoint between midnight and 3 a.m.) [2]. Oura also measures resting heart rate, body temperature and movement while you sleep [1].
  • Readiness Score (same bands): Resting Heart Rate, HRV Balance, Body Temperature, Recovery Index, Sleep, Sleep Balance, Sleep Regularity, Previous Day Activity and Activity Balance. Most compare you with your own long-term average [3].
  • Weightings: not published.

WHOOP

  • Recovery: 0–100%. Green 67–100%, yellow 34–66%, red 0–33%. It uses resting heart rate, heart rate variability, respiratory rate, sleep, skin temperature and blood oxygen [4]. The data WHOOP shares with developers reports HRV as RMSSD [5].
  • Sleep: WHOOP tracks how long you slept and your light, REM and deep (slow-wave) sleep, and sets your sleep need from your sleep debt and the previous day’s activity [4].
  • Sleep Performance: WHOOP’s support site, which describes how this score is built, could not be loaded when we checked, so we don’t list its parts here.
  • Weightings: not published.

Apple Watch

  • Sleep Score: duration up to 50 points, bedtime consistency up to 30 (when you fell asleep over the last 13 nights), interruptions up to 20 (how often you woke and for how long) [6].
  • Bands: Very Low 0–40, Low 41–60, OK 61–80, High 81–95, Very High 96 and above [6].
  • Stages: the watch shows Awake, REM, Core and Deep [7]. Apple’s score page doesn’t list stages as a score input [6].

Garmin

  • Sleep Score: 0–100, based on how long and how well you slept. Quality includes your sleep stages and your average stress score during sleep, which is based on HRV. Stages come from heart rate, HRV and movement [8].
  • Bands: Excellent 90–100, Good 80–89, Fair 60–79, Poor below 60 [9].
  • Training Readiness (1–100): uses last night’s sleep score, recovery time, HRV status, acute training load, sleep history (last 3 nights) and stress history (last 3 days). Zones run from Poor (1–24) to Prime (95–100) [10].
  • Weightings: not published.

Common mistakes

  • Comparing scores across brands. The bands differ: 80 is “Good” on Garmin, “Good” on Oura and “OK” on Apple. The inputs differ too.
  • Chasing the stage numbers. Deep and REM feed some scores, but stages are the part wearables estimate worst; see accuracy.
  • Treating the score as a diagnosis. None of these scores is a medical test.

Effect on your sleep score

  • Total sleep: the largest input on every device that says so [1][6].
  • Timing and regularity: directly scored by Oura (Timing, Sleep Regularity) and Apple (bedtime consistency) [2][3][6].
  • Efficiency and wake-ups: scored by Oura, Apple and Garmin [2][6][8].
  • Deep sleep and REM: feed Oura’s and Garmin’s scores [2][8], but in a lab study of six devices, stage-by-stage agreement with polysomnography was only 50–65% [11].
  • HRV and resting heart rate: feed readiness and recovery scores more than sleep scores [3][4][10].

How confident: high that these are the inputs, because the companies say so. Unknown how the inputs are weighted, except on Apple.

Evidence

Rated Some. The list of inputs comes straight from each company’s documentation, which is the right source for what a device measures. The raw measurements have been tested against lab sleep studies: in 53 adults, all six devices tested were good at telling sleep from wake but needed improvement on stages [11].

Limits: the composite scores themselves have not, as far as we found, been tested independently. Only Apple states its weighting. Garmin’s bands come from a blog post, not a manual.

Try this week

Open your app’s sleep score and look at the contributors every morning this week. Write down which one is lowest most often. That’s the one to work on, and the habit pages on this site link to it.

Sources

  1. [1]Oura (2026). Sleep Score. Manufacturer documentation
  2. [2]Oura (2026). Sleep Contributors. Manufacturer documentation
  3. [3]Oura (2026). Readiness Contributors. Manufacturer documentation
  4. [4]WHOOP (2026). WHOOP 101. Manufacturer documentation
  5. [5]WHOOP (2026). Recovery. Manufacturer documentation
  6. [6]Apple (2026). View your Sleep Score on Apple Watch. Manufacturer documentation
  7. [7]Apple (2026). Track your sleep on Apple Watch and use Sleep on iPhone. Manufacturer documentation
  8. [8]Garmin (2026). How Garmin watches track your sleep, calculate sleep score. Manufacturer documentation
  9. [9]Garmin (2026). How well do you sleep? New data examines Garmin users' sleep. Manufacturer documentation
  10. [10]Garmin (2026). fēnix 8 Series Owner's Manual: Training Readiness. Manufacturer documentation
  11. [11]Miller DJ, Sargent C, Roach GD (2022). A Validation of Six Wearable Devices for Estimating Sleep, Heart Rate and Heart Rate Variability in Healthy Adults. Sensors. Intervention study

General information for healthy adults, not medical advice. If you have a sleep problem that lasts, read when to see a doctor. Sources checked 4 October 2026. Spot a mistake? Tell us.