Work backward from your alarm
What time should I go to bed?
Choose when you need to wake up and compare a few possible bedtime windows.
Direct answer
Start with the morning you actually have
Your wake-up time is often fixed. This bedtime calculator subtracts your selected fall-asleep estimate and 6, 5, 4, or 3 approximate cycles.
For example, a 7:30 AM alarm and 15-minute fall-asleep estimate produce 10:15 PM for six cycles, 11:45 PM for five, 1:15 AM for four, and 2:45 AM for three.
Method and limits
A planning window, not an exact bedtime
Real sleep cycles vary. Use the result to protect enough time in bed rather than trying to hit a precise biological boundary.
See the formula, sources, and limitations.
Related guide: How to keep a consistent sleep schedule
Questions, answered softly
What time should I go to bed if I wake up early?
Enter the wake-up time you need. The calculator works backward using your fall-asleep estimate and four cycle counts: 6, 5, 4, and 3 approximate 90-minute windows.
Why are there several bedtimes?
There is no single exact bedtime produced by a cycle estimate. Multiple options help you compare a longer sleep opportunity with shorter alternatives.
Is the latest bedtime recommended?
It is shown only as a short-night reference. When possible, prefer a schedule that gives you enough total sleep for your needs.