(Most adults need 5-6 complete sleep cycles per night)
Have you ever woken up feeling groggy even after 8 hours of sleep? Or found yourself wide awake at bedtime? The secret to better sleep isn't just quantity—it's about timing your sleep with your natural sleep cycles.
Our sleep calculator helps you find the perfect bedtime or wake-up time based on the science of sleep cycles. Each cycle lasts about 90 minutes, and waking up between cycles (rather than in the middle) helps you feel more refreshed.
Select whether you want to calculate your ideal bedtime based on when you need to wake up, or calculate your ideal wake-up time based on when you plan to go to bed.
Input your target wake-up time or bedtime using the simple time picker. The calculator works with both AM/PM and 24-hour formats.
Customize how many sleep cycles (90-minute periods) you want to target. Most adults need 5-6 complete sleep cycles per night.
The calculator shows you multiple options around your optimal sleep time, helping you find the best time to wake up or go to bed.
Sleep isn't just one continuous state. Throughout the night, your brain cycles through different stages of sleep:
A complete sleep cycle lasts about 90 minutes, moving through all these stages. Waking up at the end of a cycle (during lighter sleep) helps you feel more refreshed than waking in the middle of deep sleep.
Going to bed and waking up at the same time every day helps regulate your body's internal clock.
Avoid screens 1 hour before bedtime as blue light can suppress melatonin production.
Keep your room cool (60-67°F), dark, and quiet for optimal sleep conditions.
Avoid caffeine after 2pm as it can stay in your system for 6-8 hours.
Most adults need 5-6 complete sleep cycles per night (7.5-9 hours). The calculator defaults to 6 cycles (9 hours) but you can adjust this based on your personal needs.
The calculator shows multiple options around your optimal time. Choose the one that best fits your schedule. Consistency is more important than perfection.
For naps, aim for either 20-30 minutes (before deep sleep) or a full 90-minute cycle. Waking in between may leave you feeling groggy.