Better sleep starts here
Wake up refreshed, every single morning.
Find the perfect bedtime or wake-up time based on your body's natural 90-minute sleep cycles — so you rise clear-headed instead of groggy.
Sleep Cycle Information
A good night's sleep consists of 5-6 complete sleep cycles. Our calculator helps you align your sleep with these natural rhythms.
Why it works
Designed around how you actually sleep
90-minute cycles
Times your sleep to complete full cycles, not interrupt them.
Wake-up windows
Shows several options so you can pick what fits your schedule.
Fall-asleep buffer
Accounts for the ~15 minutes most people take to drift off.
Works everywhere
Fast, installable web app that works on any device, offline.
Why it works
Why Sleep Cycles Matter
Sleep isn't just about the number of hours—it's about quality and timing. Your body goes through natural 90-minute sleep cycles, each consisting of light sleep, deep sleep, and REM (dream) sleep. Waking during a light phase leaves you refreshed; waking during deep sleep leaves you groggy.
5-6 Complete Cycles
Adults need 5-6 complete 90-minute cycles for optimal health and cognition.
Science-Backed Timing
Our calculator uses research-proven sleep architecture to find your best bedtimes.
15-Min Fall-Asleep Buffer
We account for average sleep onset latency so you wake at optimal times.
From the Blog
Explore our latest articles on sleep science, tips, and health.
Complete Your Health Picture
Sleep is one pillar of wellness. Explore our other health calculators—BMI, age, water intake, and more—to optimize every aspect of your health.
Explore All ToolsFrequently Asked Questions
This calculator provides general guidance based on sleep science research. Consult a healthcare provider for personalized sleep advice or if you suspect a sleep disorder.