Sleep TilesSleep calculator
Enter the time you need to wake up and get bedtimes that line up with whole sleep cycles, or start from when you're going to bed. It allows for the time it takes to fall asleep.
How the calculator works
It counts in whole sleep cycles. An average cycle lasts about 90 minutes, and Cleveland Clinic says you ideally need four to six of them every 24 hours. Then it adds the time it takes to fall asleep, 15 minutes unless you change it.
Say you need to be up at 7:00 AM. Five cycles is 7 hours 30 minutes of sleep. Add 15 minutes to drift off and your bedtime is 11:15 PM. Six cycles moves it to 9:45 PM, and four cycles to 12:45 AM.
Why the times are a starting point
Ninety minutes is an average, not a rule. A review in the journal Sleep describes a typical night as 4 to 6 cycles, each lasting roughly 90 to 110 minutes. If you know your nights run on longer cycles, change the cycle length above and the times move with it.
The time to fall asleep varies too. A commonly cited healthy range is about 10 to 20 minutes, according to Cleveland Clinic, which also says that's not a strict rule. Dozing off within a few minutes of lying down can be a sign you're overtired.
Counting in whole cycles is meant to avoid an alarm in the middle of deep sleep. Waking from deep sleep can leave you disoriented and foggy for up to 30 minutes or an hour, Cleveland Clinic says. Since cycles vary from person to person and through the night, no calculator can know exactly where you'll be in yours.
How much sleep you need by age
Results under 7 hours are marked because the American Academy of Sleep Medicine recommends 7 or more hours a night for adults on a regular basis. Here are the CDC's figures for older children and adults:
| Age | Recommended sleep |
|---|---|
| 6 to 12 years | 9 to 12 hours |
| 13 to 17 years | 8 to 10 hours |
| 18 to 60 years | 7 or more hours |
| 61 to 64 years | 7 to 9 hours |
| 65 and older | 7 to 8 hours |
See whether the new bedtime sticks
A calculator plans one night. Your tracker shows what actually happened. If an Apple Watch, Oura Ring, WHOOP or Garmin saves your sleep to Apple Health, Sleep Tiles scores each night out of 100, checks your bedtime against a window you set and turns the night into a colored tile, so after a few weeks you can see whether the earlier bedtime is holding.
Sources
- Sleep: how much you need and its 4 stages, Cleveland Clinic
- What is sleep latency?, Cleveland Clinic
- Sleep: a health imperative, Sleep (2012)
- Recommended amount of sleep for a healthy adult, American Academy of Sleep Medicine and Sleep Research Society
- About sleep, Centers for Disease Control and Prevention
Questions
What time should I go to bed if I wake up at 6 AM?
Allowing 15 minutes to fall asleep, 10:15 PM gives you five 90 minute cycles (7 hours 30 minutes asleep). 8:45 PM gives six cycles, and 11:45 PM gives four cycles, which is only 6 hours.
How many sleep cycles do I need?
Cleveland Clinic says you ideally need four to six cycles every 24 hours. At about 90 minutes each, that's 6 to 9 hours.
How long should it take to fall asleep?
About 10 to 20 minutes is a commonly cited healthy range, according to Cleveland Clinic. If it consistently takes an hour or more most nights, it suggests talking to a healthcare provider.
Is 6 hours of sleep enough?
For most adults, no. The American Academy of Sleep Medicine recommends 7 or more hours a night on a regular basis. Four cycles is 6 hours, which is why the calculator marks it as under 7 hours.
