Sleep Calculator: Find Your Perfect Bedtime & Wake-Up Time
Stop waking up groggy. Our Sleep Calculator helps you harness the science of sleep cycles to find the perfect time to go to bed and wake up. By aligning your sleep with your body's natural rhythm, you can wake up feeling refreshed, energized, and ready for the day. Enter your time below and let our calculator do the rest.
Your Age (Optional)
Select your age for personalized sleep recommendations based on health guidelines.
I Want to Wake Up At...
Enter your desired wake-up time, and we'll tell you the best times to go to bed.
I'm Going to Bed At...
Enter your planned bedtime, and we'll tell you the best times to wake up.
I Want to Sleep For...
Enter your planned bedtime and desired sleep length, and we'll find your wake-up time.
Your Guide to Better Sleep
This tool uses sleep science to help you feel your best. By aligning your alarm with your body's natural rhythm, you can avoid morning grogginess and improve your overall sleep quality.
Understanding Sleep Cycles: The Science
A full sleep cycle lasts about 90 minutes and consists of different stages, including light sleep, deep sleep, and REM sleep. Waking up during a deep sleep stage is what causes that tired, groggy feeling. Our sleep cycle calculator finds the best times to wake up—right at the end of a cycle when you're in a lighter stage of sleep.
Your Sleep Questions, Answered
How does this sleep calculator work?
It calculates in 90-minute blocks, the length of an average sleep cycle. For bedtimes, it works backward from your wake-up time and adds 15 minutes for falling asleep. This ensures your alarm rings when you are in your lightest stage of sleep.
Why is it important to wake up between sleep cycles?
Waking up mid-cycle, especially from deep sleep, causes sleep inertia—that groggy, disoriented feeling. Finishing a full cycle allows you to wake up from light sleep, making you feel alert and refreshed.
How much sleep do I actually need?
Most adults need 7-9 hours, which is about 5-6 full sleep cycles. However, needs vary by age. Our calculator lets you select your age to see recommendations based on guidelines from the National Sleep Foundation.
What are the stages of a sleep cycle?
A 90-minute sleep cycle moves through four stages: Stage N1 (light sleep), N2 (deeper sleep), N3 (deepest, restorative sleep), and REM (Rapid Eye Movement) sleep, where dreaming occurs. The cycle then repeats.