Sleep Calculator
Find the best time to go to bed or wake up so you finish complete 90-minute sleep cycles and wake up feeling less groggy.
Runs on your device
Result
Results appear here as you type.
What it does
Sleep runs in cycles of roughly 90 minutes. Waking at the end of a cycle, rather than in deep sleep, tends to feel easier. The calculator also allows about 14 minutes to fall asleep.
How to use it
- Choose whether you know your wake up time or your bedtime.
- Enter the time.
- Pick one of the suggested times.
Example
To wake at 7:00 AM, go to bed around 9:46 PM, 11:16 PM, 12:46 AM or 2:16 AM. Select Try an example above to see it.
When it helps
- Planning bedtime before an early flight.
- Shift work.
- Building a consistent routine.
Questions
How much sleep do adults need?
Most adults need 7 to 9 hours, which is 5 or 6 cycles.
Are cycles always 90 minutes?
They vary from about 70 to 120 minutes between people and through the night, so treat the times as a guide.
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