Is 6 Hours of Sleep Enough?
Six hours of sleep is usually not enough. It is an hour below the 7-hour minimum the AASM recommends for adults, and in a well-known 2003 study, two weeks of 6-hour nights impaired attention as much as a full night without sleep, even though participants felt only mildly tired.
Bedtimes for 6 hours of sleep
Each bedtime includes 15 minutes to fall asleep.
Enough for adults?
Usually not
Sleep cycles
4
Sleep debt per week vs. 7 h
7 h
| To wake up at | Go to bed at |
|---|---|
| 5:30 AM | 11:15 PM |
| 6:00 AM | 11:45 PM |
| 6:30 AM | 12:15 AM |
| 7:00 AM | 12:45 AM |
| 7:30 AM | 1:15 AM |
| 8:00 AM | 1:45 AM |
Want a different wake-up time? The sleep calculator finds bedtimes that end on a full sleep cycle.
What the research says about 6 hours of sleep
Six hours does line up neatly with four full 90-minute sleep cycles, so waking at the 6-hour mark tends to feel easier than 5 or 6.5 hours. That makes 6 hours a reasonable plan for an occasional short night, but as a regular schedule it adds up to about 7 hours of sleep debt a week. A small number of people carry gene variants that let them function on about 6 hours, but they are rare.
How much sleep you need by age
These are the National Sleep Foundation's recommended ranges.
| Age | Hours per night |
|---|---|
| School-age children (6–13) | 9–11 |
| Teenagers (14–17) | 8–10 |
| Adults (18–64) | 7–9 |
| Older adults (65+) | 7–8 |
Other sleep lengths
- Is 3 hours of sleep enough?
- Is 4 hours of sleep enough?
- Is 5 hours of sleep enough?
- Is 6.5 hours of sleep enough?
- Is 7 hours of sleep enough?
- Is 8 hours of sleep enough?
- Is 9 hours of sleep enough?
Running short most nights? The sleep debt calculator shows how much you owe and how long it takes to pay back.
More free sleep tools
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Best bedtime or wake-up time based on 90-minute sleep cycles.
Nap Calculator
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Sleep Debt Calculator
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REM Sleep Calculator
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Jet Lag Calculator
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Sleep Efficiency Calculator
What share of your time in bed you actually spend asleep.
Sleep Schedule Calculator
A day-by-day plan to fix your sleep schedule or adjust to daylight saving time.
Caffeine Calculator
How much caffeine is left at bedtime and when to have your last coffee.
Chronotype Quiz
Five questions to find out if you are a morning lark or a night owl.
Frequently asked questions
Is 6 hours of sleep enough?
Six hours of sleep is usually not enough. It is an hour below the 7-hour minimum the AASM recommends for adults, and in a well-known 2003 study, two weeks of 6-hour nights impaired attention as much as a full night without sleep, even though participants felt only mildly tired.
How many sleep cycles is 6 hours of sleep?
Exactly 4 sleep cycles of about 90 minutes, so waking at the 6-hour mark usually lands in light sleep.
What time should I go to bed to get 6 hours of sleep?
Count back 6 hours and 15 minutes from your alarm. To wake at 7:00 AM, go to bed at 12:45 AM.