Sleep Calculator

What Sleep Calculator is

Wake-at or sleep-now times on 90-minute cycles, with a fall-asleep buffer you can change. It is cycle arithmetic, not medical advice.

How to use it

1. Pick wake at or sleep now.
2. Set the clock time, fall-asleep minutes, and cycle length if you need to.
3. Read the suggested bed or wake times.
4. Copy the summary if you want it in a note.

Common uses

Pick a bedtime that lands near a cycle boundary, or see when to set an alarm if you go to sleep now. Five or six cycles is the usual range. Shift work, caffeine, and a baby do not fit this model.

Privacy

Numbers and text stay in this tab. We do not log them. Refresh the page and the form is blank. We never see what you copy.