Healthy adults typically spend about 20 percent of the night in deep sleep and 20 to 25 percent in REM sleep. For a 7 to 8 hour night, that is roughly 84 to 96 minutes of deep sleep. No official body sets a required number of deep or REM minutes. The real goal is enough total sleep, and your brain sorts out the stages.
Have your stage minutes from a tracker? Check your shares with the sleep stage percentage calculator.
How Much Deep Sleep Should You Get Per Night?
About 20 percent of the night is the typical adult figure. The American Thoracic Society (ATS) primer for reading sleep studies gives typical adult shares of about 5 percent for light stage N1, 50 percent for N2, 20 percent for deep sleep (N3) and 20 to 25 percent for REM (ATS primer).
For a 7-hour night, 20 percent is roughly 84 minutes. For an 8-hour night, it is about 96 minutes. These are typical amounts, not a pass mark. A night a little above or below is normal, and the shares shift from person to person and with age. If you want to know what deep sleep actually does for the body and brain, read what is deep sleep.
Average REM Sleep Per Night
REM is typically 20 to 25 percent of an adult’s night in the ATS primer. That works out to about 84 to 105 minutes in 7 hours and 96 to 120 minutes in 8 hours. The first REM period usually starts about 60 to 120 minutes after you fall asleep.
So how much REM sleep is needed? As with deep sleep, no source sets a fixed minimum. A normal share inside a full night is what matters. The two stages do different jobs, which is explained in deep sleep vs REM sleep.
How Much Light Sleep Do You Need?
Light sleep is stages N1 and N2, and it is the biggest part of the night. In the ATS primer, N2 is about half of sleep time and N1 is about 5 percent. A lot of light sleep is normal. It is not a sign of poor sleep on its own.
Light sleep also works as the doorway between the deeper stages. You pass through it each time you move from one cycle to the next. For a full tour of all four stages, see stages of sleep.
Typical Stage Shares For 7 And 8 Hour Nights
| Stage | Typical Share | 7 Hours (Calculated) | 8 Hours (Calculated) |
|---|---|---|---|
| Light, N1 | About 5 percent | About 21 min | About 24 min |
| Light, N2 | About 50 percent | About 3.5 h | About 4 h |
| Deep, N3 | About 20 percent | About 84 min | About 96 min |
| REM | 20 to 25 percent | 84 to 105 min | 96 to 120 min |
The minutes are worked out from the ATS percentages, so treat them as examples. Real nights vary, and the numbers do not add up to exactly 100 percent because brief awakenings are left out.
Why Deep Sleep Comes Early And REM Comes Late
Deep sleep is front-loaded. NHLBI says deep sleep is most common in the first part of the night, while REM is more common later. One trip through all the stages takes about 80 to 100 minutes, and most people get 4 to 6 of these cycles a night (NHLBI).
This timing has a practical side. Cutting a night short by waking early mostly costs you REM, because the longest REM periods come near morning. Going to bed very late but waking at the usual time shortens the whole night, so it cuts into both. Planning your wake-up around full cycles is the idea behind the 90-minute sleep cycle calculator.
How Much Deep Sleep Do You Need By Age?
Deep sleep changes across life. NHLBI says newborns spend more of their sleep in REM. Slow-wave sleep, the deepest stage, peaks in early childhood, drops sharply in the teen years and keeps declining through adulthood. Older people may not have any slow-wave sleep at all, according to the same NHLBI page.
Research on healthy adults is mixed on how large the drop in deep and REM shares really is. Total sleep time and sleep quality tend to slip with age too, so a lower deep sleep number in your 60s is not, on its own, a sign that something is wrong.
The details are covered in how much sleep older adults need. Children and teens still need the most total sleep, and their ranges are in children’s sleep by age.
Do You Need A Set Number Of Minutes?
No. The CDC gives targets for total sleep only: 7 or more hours for ages 18 to 60, 7 to 9 hours for ages 61 to 64, and 7 to 8 hours for ages 65 and over (CDC). There is no matching target for deep or REM minutes.
This is good news. If you protect your total sleep, the stages tend to take care of themselves. Start with the right total for you using the sleep calculator by age and gender. The bigger picture of total sleep need is covered in the guide on how much sleep you need.
A Worked Example
Say your tracker shows 7 hours 10 minutes asleep, with 1 hour 20 minutes of deep sleep and 1 hour 35 minutes of REM. In minutes, that is 430 asleep, 80 deep and 95 REM.
Deep sleep is 80 divided by 430, or about 19 percent. REM is 95 divided by 430, or about 22 percent. Both sit close to the typical shares above. If one of your numbers looks very different, do not panic. Trackers misjudge stages, as the next section explains. To plan a wake time that lands after a REM period, try the REM sleep calculator.
What Your Tracker Can And Cannot Tell You
A sleep lab sorts stages by recording brain waves. Most watches, rings and phone apps cannot do that. They estimate stages from movement and heart rate instead, so their deep and REM numbers are educated guesses.
Trackers are more useful for trends than for single nights. Look at your average over two to four weeks, and compare it with how you feel during the day. A tracker that shows low deep sleep while you wake up rested is more likely a tracker problem than a sleep problem. Read are sleep trackers accurate before you act on any one reading.
How To Support Healthy Sleep Stages
You cannot force deep sleep, but good habits give your brain the best chance. The CDC advises the same bed and wake time every day, a quiet, relaxing and cool bedroom, turning off devices at least 30 minutes before bed, avoiding caffeine in the afternoon or evening, and exercising regularly with a healthy diet.
Of these, a steady schedule and enough time in bed matter most, because deep sleep needs a full night to unfold. Caffeine timing is the easiest to check. Enter your last cup into the caffeine impact calculator to see how much may still be active at bedtime. For more on how the sleep system works as a whole, visit how sleep works.
When Low Deep Or REM Sleep May Signal A Problem
A single odd night is not a problem. Everyone has nights with less deep sleep than usual, often after stress, travel or a late bedtime. A pattern of poor sleep with daytime effects is different. A tracker cannot diagnose anything, but a sleep study can, because it measures the stages directly with brain-wave sensors.
When to see a doctor: talk to a doctor if poor sleep lasts for weeks, keeps getting worse, or leaves you very sleepy in the day.
Also get checked if someone says you snore loudly, stop breathing or gasp in your sleep. Those can be signs of sleep apnea, explained in obstructive sleep apnea symptoms. If you nod off while driving, stop driving and seek help soon.
FAQs About How Much Deep Sleep You Need
Is One Hour Of Deep Sleep Enough?
For a 7 to 8 hour night, an hour is a little below the typical 84 to 96 minutes but within normal variation. No official minimum exists, so judge by how rested you feel.
Is Light Sleep Bad?
No. Light sleep is the largest part of a normal night. Stage N2 alone is about half of sleep time in healthy adults.
Why Does My Tracker Show Low REM?
Most trackers guess stages from movement and heart rate, so low REM is often a device error. If it stays low and you feel unwell, ask a doctor.
Do Deep And REM Sleep Fall With Age?
Deep sleep peaks in early childhood and declines through adulthood. How much the adult shares change is debated, while total sleep tends to slip with age.
What Is The Difference Between Deep Sleep And REM?
Deep sleep, also called slow-wave sleep, is most common early in the night. REM comes later, when your eyes twitch, your brain is active and most dreaming happens.