Sleep Calculator
Pick whether you want to wake up at a set time or are going to bed now — get the best times based on 90-minute sleep cycles (plus ~15 min to fall asleep).
How to use the Sleep Calculator
- Choose wake-up time or going to bed now.
- Set the time if needed.
- Pick one of the suggested cycle times.
100% free, no sign-up, and it all runs in your browser — your data never leaves your device.
FAQ
Why 90 minutes?
A full sleep cycle is roughly 90 minutes; waking at the end of a cycle helps you feel more rested.