Wake up feeling refreshed
What time do you
want to wake up?
Work backwards through complete sleep cycles and find your ideal bedtime in seconds.
Your ideal bedtimes
Try to be in bed at one of these times
These suggestions are estimates. Consistent sleep habits matter just as much as timing.
A full sleep cycle lasts about 90 minutes.
Most adults feel best after
5–6 complete cycles.
The simple science
Sleep in cycles, not just hours.
Waking between sleep cycles may help you feel less groggy. This calculator counts backwards from your alarm in 90-minute blocks, then adds a short window for falling asleep.