Sleep calculator (bedtime by sleep cycles)
Pick whether you know your wake-up time or your bedtime. The time it takes to fall asleep is added.
Result
11:15 PMSuggested bedtime (5 cycles, 7 h 30 of sleep)
- 6 cycles (9 h of sleep)
- 09:45 PM
- 4 cycles (6 h of sleep)
- 12:45 AM
- 3 cycles (4 h 30 of sleep)
- 02:15 AM
Inputs
- I know
- My wake-up time
- Time
- 07:00
- Time to fall asleep
- 15
How it is calculated
A sleep cycle lasts about 90 minutes on average.
Result
Suggested bedtime (5 cycles, 7 h 30 of sleep)
- 6 cycles (9 h of sleep)
- 09:45 PM
- 4 cycles (6 h of sleep)
- 12:45 AM
- 3 cycles (4 h 30 of sleep)
- 02:15 AM
How it is calculated
- A sleep cycle lasts about 90 minutes on average.
- Bedtime = wake-up − (cycles × 90 min + time to fall asleep). Wake-up = bedtime + the same span.
Example
Wake-up at 07:00, 15 min to fall asleep: go to bed at 23:15 (5 cycles), or 21:45 (6 cycles), 00:45 (4 cycles), 02:15 (3 cycles).
Good to know
- Indicative only: cycle length varies between people and through the night.
- This is not medical advice. For ongoing tiredness or sleep problems, see a health professional.
Frequently asked questions
What is this tool used for?
Pick whether you know your wake-up time or your bedtime. The time it takes to fall asleep is added.
How is the result calculated?
A sleep cycle lasts about 90 minutes on average.
What should I check before using the result?
Indicative only: cycle length varies between people and through the night.