How to find your best bedtime or wake-up time
- Under "What do you want to know?", choose "Go to bed" if you know when you must get up, or "Wake up" if you know when you are going to bed.
- Enter the time and how many minutes you usually need to fall asleep.
- Pick one of the listed times. Each is a whole number of 90-minute cycles after you fall asleep.
- Choose "Sleep now" to see when to wake if you go to sleep right away.
Times are shown in your device's usual 12-hour or 24-hour format. Aim for 5 or 6 cycles most nights, and keep your bedtime steady, since a regular schedule helps more than any single trick.
Questions
Is my data uploaded or stored?
No. The times are worked out in your browser. The "Sleep now" option reads your device clock once and does not send it anywhere.
What is a sleep cycle?
During the night you move through light sleep, deep sleep, and REM sleep in a loop that lasts about 90 minutes. Waking near the end of a loop usually feels easier than waking in the middle of deep sleep.
How many cycles should I aim for?
Five or six cycles, which is 7.5 to 9 hours, suit most adults. Four cycles (6 hours) is a minimum for an occasional short night. Those with five or six are marked as recommended.
Why does the tool ask how long it takes me to fall asleep?
Cycles start when you fall asleep, not when you get into bed. The tool adds or subtracts that time. The default is 15 minutes, so change it if you drop off faster or slower.
Is the 90-minute rule exact?
No. Cycle length varies between people and through the night, usually between 80 and 110 minutes. Treat the times as a good starting point and adjust to how you feel in the morning. This is not medical advice.
Credits
Built by OneTooling using standard browser features. No third-party code runs on your data.