Free tool
Sleep Calculator – When to Go to Bed
Find the best time to go to bed or wake up, based on 90-minute sleep cycles, so you wake up between cycles instead of in deep sleep.
I want to wake up at
I’m going to bed at
Times include about 14 minutes to fall asleep. Adjust: .
Why sleep cycles matter
During the night you pass through cycles of light, deep and REM sleep that last roughly 90 minutes each. Waking up at the end of a cycle, when sleep is lightest, usually feels much easier than being woken in the middle of deep sleep – even if you slept less.
Most adults need 7–9 hours, which is five or six full cycles. The suggested times marked ★ give you the healthiest amount. Cycle length varies from person to person, so treat the times as a guide and adjust by 10–15 minutes if you still wake up groggy.
Frequently asked questions
How long is a sleep cycle?
A full sleep cycle lasts about 90 minutes on average, although it can range from roughly 70 to 120 minutes. Most people go through four to six cycles a night.
What time should I go to bed to wake up at 7am?
For six full cycles go to bed around 9:46pm, for five cycles around 11:16pm – both include about 14 minutes to fall asleep.