Wake up between cycles, not mid-cycle

Sleep Cycle Calculator

Pick a wake-up time or sleep right now, and see bedtimes or wake times timed to complete 90-minute sleep cycles.

Counts back in 90-minute sleep cycles, plus a 15-minute buffer to fall asleep.

How it works

1

Choose a mode

Tell it when you want to wake up, or that you're heading to bed right now.

2

See cycle options

Get several times, each showing how many full 90-minute sleep cycles you'd complete.

3

Pick a time

Aim for a bedtime or wake time that lines up with the end of a cycle, not the middle.

FAQ

Why 90-minute cycles?

Sleep moves through repeating stages roughly every 90 minutes. Waking near the end of a cycle, rather than in the middle of deep sleep, tends to feel less groggy.

Why subtract or add 15 minutes?

That's a typical buffer for the time it takes to actually fall asleep after getting into bed, so the cycle count starts from when you're really asleep.

How many cycles should I aim for?

Five to six cycles (about 7.5 to 9 hours) is a common target for adults, but individual sleep needs vary.

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