Sleep Calculator
Free sleep calculator online. Find bedtime or wake time from 90-minute sleep cycles.
How this sleep calculator finds bedtime and wake time
Use this free sleep calculator online to plan bedtime or wake-up time around 90-minute sleep cycles. Most people fall asleep in about 15 minutes, then move through light, deep, and REM sleep in each cycle.
Pick Find bedtime from wake time if you know when you must get up. Pick Find wake time from bedtime if you know when you can go to sleep. The page shows 6, 5, and 4 cycle options so you can choose about 9, 7.5, or 6 hours of sleep.
This sleep cycle calculator is a planning aid, not medical advice. Teens, shift workers, and people with sleep disorders may need a different schedule. Pair it with the age calculator only for general health tracking.
sleep calculator FAQ
It adds 15 minutes to fall asleep, then counts 90-minute sleep cycles. You get three suggested times for 6, 5, and 4 cycles.
Yes. This bedtime and wake time calculator is free. There is no account or paywall.
Many adults feel better with 7 to 9 hours. That is usually 5 or 6 complete 90-minute cycles plus time to fall asleep.
No. Wake time and bedtime stay in your browser.