Sleep Calculator

Free online sleep calculator. Optimal bedtime/wake-up time. Track your health in your browser.

Wake time

Fall asleep (min)

Recommended Bedtimes

9:46 PM6 sleep cycles (9h 14m)

11:16 PM5 sleep cycles (8h 44m)

12:46 AM4 sleep cycles (6h 14m)

2:16 AM3 sleep cycles (5h 44m)

3:46 AM2 sleep cycles (3h 14m)

About Sleep Cycles

A full sleep cycle lasts about 90 minutes. Waking up at the end of a cycle (rather than in the middle of deep sleep) leaves you feeling more rested. The calculator adds 14 minutes to account for the average time it takes to fall asleep.

Each cycle includes light sleep, deep sleep, and REM sleep. Aim for 5-6 complete cycles per night (7.5-9 hours).