Sleep Cycle Calculator
Wake up refreshed. Find the best time to sleep or wake up based on your body's natural 90-minute sleep cycles.
Sleep Debt Tracker
Enter hours slept each night (goal: 8h/night):
Best Nap Times
When do you want to start your nap?
Wake up at 2:20 PM
Boosts alertness without grogginess — stays in light sleep
Wake up at 3:30 PM
Full sleep cycle — deep rest and memory consolidation
How Do Sleep Cycles Work?
Your sleep is divided into 90-minute cycles of light sleep, deep sleep, and REM sleep. Waking mid-cycle causes grogginess — waking at the end of one feels natural. This calculator adds 14 minutes for the average time to fall asleep, so your results are precisely timed.
Learn more about sleep cycles →