Anirva sells Sleep Harmony, a dietary supplement. This article shares research for general education and is not medical advice.
If you've looked at your sleep tracker and wondered whether your deep sleep number is high enough, you're in good company. The honest answer is that there are typical ranges, and no official target for each stage. Here are the ranges, where sources differ, and why tracker numbers are estimates.
In this article
- Typical ranges: deep sleep is roughly 10% to 25% of the night depending on the source, and REM sleep is about 20% to 25%. [1][2][4]
- On a 7 to 8 hour night, that's roughly 40 to 120 minutes of deep sleep and 85 to 120 minutes of REM sleep.
- Guidelines set total hours, not minutes per stage. Adults are advised to sleep 7 or more hours a night. [8]
- Deep sleep and REM percentages decline with age, so a lower number at 60 than at 25 is expected. [6]
- Trackers estimate stages. In one study, a smart ring labeled 35% of lab-scored deep sleep as light sleep. [12]
Facts at a Glance
| Fact | Detail |
|---|---|
| Deep sleep share | 10%–25% of total sleep, depending on the source [1][2][4] |
| REM sleep share | 20%–25% across most sources [1][4] |
| Age effect | Both shares decline with age; REM ~0.6 points/decade from 19–75 [6][7] |
| Tracker accuracy | One ring mislabeled 35% of lab-scored deep sleep as light sleep [12] |
| Last reviewed | [DATE] |
How the Stages Fit Together
Sleep moves through light sleep, deep sleep and REM sleep in cycles through the night. Light sleep includes stage 1, which is brief, and stage 2, which fills about half the night. Some apps call stage 2 "core" sleep. [4] Deep sleep, also called stage 3 or slow-wave sleep, occurs mostly in the first third of the night. [1] REM sleep tends to take over in the second half.
Typical Ranges for Each Stage
Sources give slightly different ranges for deep sleep. Medscape Reference lists 10% to 20% of total sleep time. [1] Cleveland Clinic says about 25%. [2] A Texas Health guide gives 13% to 23%. [4] REM sleep is steadier across sources, at about 20% to 25%. None of these is an official target, so it helps to think of a band rather than a number.
| Stage | Share of the Night | On a 7-Hour Night | On an 8-Hour Night |
|---|---|---|---|
| Light sleep, stage 1 | 2%–5% | ~10–20 min | ~10–25 min |
| Light/"core" sleep, stage 2 | 45%–55% | ~190–230 min | ~215–265 min |
| Deep sleep, stage 3 | 10%–25%, depending on source | ~40–105 min | ~50–120 min |
| REM sleep | 20%–25% | ~85–105 min | ~95–120 min |
The minutes are our arithmetic from the percentages, rounded, and the percentages are shares of time asleep, not time in bed.
There's No Official Target for Each Stage
There is no official target for each stage. The AASM and Sleep Research Society advise that adults sleep 7 or more hours a night on a regular basis. [8] Their statement notes that individual sleep need varies with genetic, behavioral, medical and environmental factors. [9] It sets hours of sleep, not minutes of deep sleep or REM sleep.
Your body also adjusts on its own. Sleep scientists note that the amount of deep sleep follows how long you have been awake. [5] Cleveland Clinic explains that your body tries to fit stage 3 sleep in as early as it can. [2]
How the Numbers Change With Age
Sleep changes across a lifetime. A meta-analysis of 65 studies that included 3,577 healthy people aged 5 to 102 found a clear pattern in adults: the percentages of slow-wave sleep and REM sleep, along with total sleep time and sleep efficiency, decreased with age, while percentages of light sleep increased. [6] The size of these effects depended on how carefully people were screened.
A review of sleep in normal aging describes REM decreasing by about 0.6 percentage points per decade from age 19 to 75. [7] Cleveland Clinic notes that children need more stage 3 sleep, and the older you get, the less you need. [2] A lower deep sleep number at 60 than at 25 is expected.
Why Your Tracker's Numbers Are Estimates
Sleep trackers estimate stages from movement and heart signals, and they do not record brain waves. The American Academy of Sleep Medicine has stated that consumer sleep devices are unable to diagnose sleep disorders, and it advised that anyone dissatisfied with their sleep talk with a licensed provider, regardless of what a device reports. [10]
Accuracy varies by device and by person. In a 2024 study of 35 adults, all three devices detected sleep versus wake well, with sensitivity of at least 95%. For sleep stages, sensitivity ranged from 50% to 86%. [11] One ring matched the sleep lab on average for deep sleep, while two other devices underestimated it by 15 and 43 minutes. In a study of 96 adults, that ring labeled 35% of lab-scored deep sleep as light sleep. [12]
Worth knowing: Averages can hide big differences between people. In a 2025 study of sleep-clinic patients, a ring's deep sleep estimate was off by about 6 minutes on average. The spread between individuals was large, though, with a standard deviation of 68 minutes. [13]
If you often wake unrefreshed, feel very sleepy in the day, snore loudly or wake up gasping, a healthcare provider can help look for causes. The AASM notes that a device's numbers should not stand in for that conversation. [10] A tracker number below a typical range is a reason to be curious, not a diagnosis. Alcohol, late caffeine and an irregular schedule can also shift the numbers from night to night.
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Try the Sleep Calculator →If You Like to Use a Tracker
If you like to use a tracker, a few habits make its numbers more useful. Total hours asleep are the most reliable measure. Trends over several weeks say more than a single night. How rested you feel each morning is a helpful check. Our articles on getting more deep sleep and on deep sleep supplements cover what research says about each.
The Short Version
Typical adult sleep includes roughly 10% to 25% deep sleep and 20% to 25% REM sleep, and these shares fall with age. No official guideline sets a target for each stage. Trackers give estimates, so the trend and how you feel matter more than any single night's number.
Frequently Asked Questions
How much deep sleep should I get?
How much REM sleep do I need?
What is core sleep on my sleep tracker?
Is one hour of deep sleep enough?
Why do I get less deep sleep as I age?
How accurate are sleep trackers for deep sleep?
References
- Medscape Reference. Normal sleep, sleep physiology, and sleep deprivation: normal sleep in adults, infants, and the elderly.
- Cleveland Clinic. Sleep basics. (Stage 3 about 25% of total sleep in adults; declines with age.)
- Cleveland Clinic. Here's how to get more deep sleep and REM sleep. Updated May 2025.
- Texas Health Resources. How much deep, light and REM sleep do you need?
- Zisapel N. New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. Br J Pharmacol. 2018;175(16):3190–3199. (Wakefulness and slow-wave sleep.) PMC6057895.
- Ohayon MM, Carskadon MA, Guilleminault C, Vitiello MV. Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals: developing normative sleep values across the human lifespan. Sleep. 2004;27(7):1255–1273. PMID 15586779; doi:10.1093/sleep/27.7.1255.
- Sleep in normal aging. Sleep Med Clin. 2018. PMC5841578.
- Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. J Clin Sleep Med. 2015;11(6):591–592. doi:10.5664/jcsm.4758.
- American Academy of Sleep Medicine. AASM and SRS publish new sleep duration consensus statement. 2015.
- Khosla S, Deak MC, Gault D, et al. Consumer sleep technology: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. 2018;14(5):877–880. doi:10.5664/jcsm.7128.
- Accuracy of three commercial wearable devices for sleep tracking in healthy adults. Sensors. 2024;24(20):6532.
- Svensson T, Madhawa K, Nt H, et al. Validity and reliability of the Oura Ring Generation 3 (Gen3) with Oura sleep staging algorithm 2.0 (OSSA 2.0) when compared to multi-night ambulatory polysomnography: a validation study of 96 participants and 421,045 epochs. Sleep Med. 2024;115:251–263.
- Herberger S, Aurnhammer C, Bauerfeind S, et al. Performance of wearable finger ring trackers for diagnostic sleep measurement in the clinical context. Sci Rep. 2025;15:9461.
