What time should I go to bed?
Enter the time you get up. The calculator counts sleep cycles backwards and gives you three bedtimes.
Pour un réveil à 07:00, couchez-vous à :
The length of a cycle varies from one person to another, and from one night to the next. The 90 minutes per cycle and 15 minutes to fall asleep are estimates. This tool gives a guide, not medical advice.
How the calculation works
A night is made of sleep cycles that follow one another. They are often counted as 90 minutes each. The calculator starts from the time you get up and subtracts 6, 5 or 4 cycles. It then subtracts another 15 minutes: the time it takes to fall asleep.
Example for getting up at 7 a.m.: 5 cycles make 7 h 30. With the 15 minutes, you should go to bed at 11:15 p.m.
The idea is simple: set your alarm for the end of a cycle rather than the middle. These figures are averages. Your own night may be shorter or longer. Take the result as a starting point, then adjust it to your mornings.
What time to go to bed to wake up at 6, 7 or 5 a.m.
Find your wake-up time in the first column. The row gives the bedtime for 6, 5 or 4 cycles, with 15 minutes to fall asleep.
| Réveil | 6 cycles9 h | 5 cycles7 h 30 | 4 cycles6 h |
|---|---|---|---|
| 5 h | 19 h 45 | 21 h 15 | 22 h 45 |
| 5 h 30 | 20 h 15 | 21 h 45 | 23 h 15 |
| 6 h | 20 h 45 | 22 h 15 | 23 h 45 |
| 6 h 30 | 21 h 15 | 22 h 45 | 0 h 15 |
| 7 h | 21 h 45 | 23 h 15 | 0 h 45 |
| 7 h 30 | 22 h 15 | 23 h 45 | 1 h 15 |
| 8 h | 22 h 45 | 0 h 15 | 1 h 45 |
Further reading
Quick questions
How long does a sleep cycle last?
It is often counted as 90 minutes. That's an average: the length varies from one person to another, and from one night to the next.
What time to go to bed to get up at 7 a.m.?
With 90-minute cycles and 15 minutes to fall asleep: 9:45 p.m. for 6 cycles, 11:15 p.m. for 5 cycles, 12:45 a.m. for 4 cycles.
Does this calculator replace medical advice?
No. It gives a guide to timing, nothing more. If your sleep worries you, talk to a health professional.