What Time Should I Sleep?
Calculate your ideal bedtime based on when you need to wake up
Most adults need 7-9 hours per night
Best Bedtimes
SLEEP INSIGHTS
Planning Your Sleep Schedule
Most people approach sleep backward—they set an alarm without considering when they need to fall asleep. This calculator flips the script, helping you plan a bedtime that ensures you get adequate rest while waking refreshed.
The magic happens when your target sleep duration aligns with complete sleep cycles. For example, if you need 8 hours and cycles are 90 minutes, you'd ideally complete 5.3 cycles. Since you can't complete partial cycles restfully, we round to whole numbers and show you how the math works out.
We also consider your fall-asleep time. If you need to wake at 7 AM and want 7.5 hours of actual sleep (5 cycles), plus 15 minutes to fall asleep, you should be in bed by 11:15 PM. Miss that window, and you'll need to wait for the next cycle alignment or wake mid-cycle.
When life doesn't allow ideal sleep, choose the "if you can't sleep earlier" alternatives. Waking after 4 complete cycles (6 hours) feels better than 6.5 hours interrupted mid-deep-sleep. Quality often trumps quantity when properly timed.
Frequently Asked Questions
The slider lets you choose your target sleep duration from 4 to 12 hours. The calculator then works backward from your wake time to find the ideal bedtime.
Quick presets are common wake-up times: Workday (7 AM), Weekend (9 AM), Early Shift (5 AM), and Night Owl (12 PM). Click any preset to instantly set that wake time.
The times shown account for the 14 minutes it typically takes to fall asleep. So yes, aim to be in bed at the time shown, and you should fall asleep at the right moment.
While this tool is designed for nighttime sleep, you can use it for longer naps. For shorter power naps, check out our dedicated Nap Calculator tool.
Most adults need 7-9 hours. If you're unsure, try our 'Sleep Needs by Age' calculator. Signs you need more: daytime fatigue, difficulty concentrating, or relying on caffeine.
Try earlier preparation: dim lights 30 minutes before, avoid screens, and keep your room cool. If you consistently can't sleep at the target time, gradually shift your schedule by 15 minutes earlier each day.
Ideally, yes! Consistent sleep times strengthen your circadian rhythm. Sleeping in on weekends can cause 'social jet lag' and make Monday mornings harder.
Recommended times give you your target sleep duration while ending on a cycle. Alternatives sacrifice some sleep time but still align with cycles, which may feel better than sleeping longer but waking mid-cycle.