Sleep Cycle Calculator

Find the best bedtime or wake time based on 90-min sleep cycles.

Wake up at

Mode

Cycle length (min)

Time to fall asleep (min)

Best bedtimes to wake refreshed

11:35 PM9 hrs sleep · 6 cycles
01:05 AM7.5 hrs sleep · 5 cycles
02:35 AM6 hrs sleep · 4 cycles
04:05 AM4.5 hrs sleep · 3 cycles
05:35 AM3 hrs sleep · 2 cycles
07:05 AM1.5 hrs sleep · 1 cycle

Sleep cycles are ~90 min on average. Waking at the end of a cycle (light sleep) leaves you refreshed; waking mid-cycle (deep sleep) leaves you groggy.

About this tool

Enter when you need to wake up, get 4 suggested bedtimes. Or enter a bedtime and get wake-up options that end on a cycle.

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