Sleep calculator
Set your wake-up time to see the best bedtimes by sleep cycle.
Sleep calculator
Find the best times to go to bed to wake up at the end of a sleep cycle, feeling refreshed rather than groggy. Enter when you need to wake up and the tool works backwards through 90-minute cycles.
How it works
Sleep runs in cycles of about 90 minutes; waking at the end of a cycle feels easier than mid-cycle. The calculator allows ~15 minutes to fall asleep, then shows bedtimes for 6, 5, 4 and 3 cycles (9, 7.5, 6 and 4.5 hours). Most adults do best with 5–6 cycles.
Frequently asked questions
How many sleep cycles should I get? Usually 5–6 (7.5–9 hours) for adults.
Why count in 90-minute blocks? Waking at the end of a cycle, rather than during deep sleep, tends to feel more refreshing.