Calculate the best times to wake up or go to sleep based on 90-minute sleep cycles.
Best Option (6 cycles)
21:45
9 hours of sleep
6 cycles (9h)
21:45
5 cycles (7.5h)
23:15
4 cycles (6h)
00:45
3 cycles (4.5h)
02:15
Sleep cycles last approximately 90 minutes each. By timing your sleep to complete full cycles, you are more likely to wake during light sleep rather than deep sleep, helping you feel more alert and refreshed.
Tracking your health metrics helps you make better lifestyle choices. You may also find our BMI Calculator useful for related calculations.
For a broader view of your finances, try the Body Fat Percentage Calculator or the Turkey Cooking Time Calculator. All of our calculators are free to use and updated for the 2026/27 tax year where applicable.
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