Bedtime Calculator: What Time Should You Go to Bed?
Bedtime Calculator
Pick when you need to wake up and we'll suggest bedtimes.
Enter the time you need to get up and the calculator counts back in 90-minute sleep cycles, adding the time it takes you to fall asleep. Each result is a bedtime that gives you a whole number of cycles.
Worked example
For a 6:00 AM wake-up, assuming 14 minutes to fall asleep:
| Go to bed at | Cycles | Sleep |
|---|---|---|
| 8:46 PM | 6 cycles | 9 hours |
| 10:16 PM | 5 cycles | 7.5 hours |
| 11:46 PM | 4 cycles | 6 hours |
| 1:16 AM | 3 cycles | 4.5 hours |
How the bedtime is worked out
The calculator takes your wake-up time, subtracts the number of cycles multiplied by 90 minutes, then subtracts your fall-asleep time. Five or six cycles (7.5 to 9 hours) are marked as recommended because most adults need seven to nine hours.
What can shift your ideal bedtime
Age, recent sleep debt, caffeine timing and your natural chronotype all change how much sleep you need. If you feel unrefreshed after a week of using a suggested time, move your bedtime 15 to 30 minutes earlier or later and see how you feel.
Frequently asked questions
Is 6 hours of sleep enough?
Most adults do best with seven to nine hours. Six hours (four cycles) is the shortest option shown, and is better treated as an occasional compromise than a routine.
Does the 90-minute rule really work?
Cycle length averages about 90 minutes but varies between people and from night to night, so treat the times as a good starting estimate rather than an exact rule.
What if I can't fall asleep in 14 minutes?
Tick the box under the calculator to enter a longer fall-asleep time, and the bedtimes move earlier to match.
Related guides and tools
- How 90-minute sleep cycles work
- What sleep latency means
- How to fall asleep faster
- How much sleep you need by age
- How to wake up feeling refreshed
Results are estimates and general information, not medical advice. Talk to a doctor if you have ongoing sleep problems.