Lifestyle & HacksFree Calculator
😴 Sleep Calculator
Find the best bedtime or wake-up time based on 90-minute sleep cycles. Wake up refreshed — not groggy.
Best times to go to sleep to wake at 7:00 AM
4:14 PM
6 cycles — 9h sleep
2:44 PM
5 cycles — 7.5h sleep
1:14 PM
4 cycles — 6h sleep
How it works
Sleep happens in 90-minute cycles. Waking up at the end of a cycle — rather than in the middle of deep sleep — leaves you feeling alert instead of groggy.
The calculator adds 14 minutes to fall asleep and then counts 90-minute cycles forward or backward from your target time.
6 cycles (9h) is ideal for recovery. 5 cycles (7.5h) suits most adults. 4 cycles (6h) is the minimum — use only occasionally.