Sleep Cycle Calculator
Wake up at the end of a sleep cycle, not in the middle of one, and start the day refreshed.
How the calculator works
- 1Choose whether you want to plan your bedtime or your wake-up time.
- 2Enter the time and press Calculate.
- 3Pick a time with 5–6 sleep cycles (7.5–9 hours) whenever possible.
Frequently asked questions
What is a sleep cycle?
A sleep cycle is roughly 90 minutes long and moves through light sleep, deep sleep and REM sleep. Waking up at the end of a cycle — instead of the middle of deep sleep — is what makes you feel refreshed.
Why does the calculator add 15 minutes?
The average person takes about 15 minutes to fall asleep, so the calculator adds this on top of your sleep cycles to give a realistic bedtime.
How many cycles do I need?
Most adults feel best with 5–6 full cycles (7.5–9 hours of sleep). Four cycles (6 hours) can work occasionally, but is not enough on a regular basis.