Sleep Calculator — Find the Best Time to Sleep or Wake
Enter a wake-up time (or the time you plan to go to bed) and get recommended sleep-cycle-aligned times so you wake up feeling refreshed.
Result:
Enter time and click Calculate to see recommended times.
How it works
This calculator uses average sleep cycle length (90 minutes) and a fall-asleep buffer to suggest times that avoid waking in the middle of a sleep cycle. Adjust the "minutes to fall asleep" for your personal sleep-onset time.
FAQ
Can I change cycle length?
Yes — individual cycles vary. You can manually adjust the computations.
What if I nap?
Naps often use shorter cycles (20–30 min or full 90-min cycles).
Why is there a fall-asleep buffer?
It accounts for the time it takes to actually fall asleep so suggested times are realistic.