Health Tool

Sleep Cycle Calculator

Find the perfect time to wake up or go to bed by aligning with your body's natural 90-minute sleep cycles.

Sleep Cycle Calculator

Calculate the best time to wake up based on 90-minute sleep cycles. Waking up between cycles leaves you feeling refreshed.

I plan to go to bed at:

Includes 15 minutes to fall asleep

Suggested Wake-up Times

07:15 AM

6 Sleep Cycles

Recommended

05:45 AM

5 Sleep Cycles

Recommended

04:15 AM

4 Sleep Cycles

02:45 AM

3 Sleep Cycles

Why sleep cycles?

A good night's sleep consists of several 90-minute cycles. Waking up mid-cycle can lead to grogginess, while waking at the end of a cycle helps you feel alert and energetic. Standard recommendations suggest getting 5 to 6 cycles of sleep.

The science of 90-minute sleep cycles

A typical human sleep cycle lasts approximately 90 minutes. During this time, the brain moves through different stages: light sleep, deep sleep, and REM (Rapid Eye Movement) sleep.

If you wake up in the middle of a sleep cycle (especially during deep sleep), you might experience "sleep inertia," which is that feeling of grogginess and disorientation. Waking up at the end of a cycle allows you to feel more alert and refreshed even if you got less total hours of sleep!

Good sleep hygiene tips

Consistency: Try to go to bed and wake up at the same time every day.
Downtime: Avoid blue light (phones/laptops) at least 30 minutes before sleep.
Environment: Keep your bedroom cool, dark, and quiet.