Sleep Cycle & Wake-Up Time Calculator

Find the best times to go to sleep or wake up feeling refreshed based on 90-minute sleep cycles.

Key Features

• Calculates 4, 5, and 6 full REM cycles (6h, 7.5h, 9h)
• Accounts for standard 14-minute sleep latency
• One-click "I am going to bed right now" calculation
• Helps eliminate sleep inertia and morning brain fog

Frequently Asked Questions

Why are 90-minute sleep cycles important?

A healthy human sleep cycle lasts approximately 90 minutes, cycling through light, deep, and REM sleep. Waking in the middle of deep sleep causes grogginess, while waking at the end of a cycle feels refreshing.