Three bedtimes that land at the end of a sleep cycle rather than in the middle of deep sleep. The default assumes 15 minutes to fall asleep; the table below covers other values.
Cycles run about 90 minutes on average, so each option is one cycle apart.
| Option | Sleep length | Go to bed at |
|---|---|---|
| Minimum | 6:00 | 22:45 |
| Recommended | 7:30 | 21:15 |
| Extended | 9:00 | 19:45 |
The times above already include 15 minutes of falling asleep. If yours is different, read the matching row.
| Falling asleep | 6 hours | 7 hours 30 | 9 hours |
|---|---|---|---|
| 5 | 22:55 | 21:25 | 19:55 |
| 10 | 22:50 | 21:20 | 19:50 |
| 15 | 22:45 | 21:15 | 19:45 |
| 20 | 22:40 | 21:10 | 19:40 |
| 30 | 22:30 | 21:00 | 19:30 |
A 5:00 alarm is common for early shifts, early flights, and for people who want an hour before the household wakes. The hard part is rarely the morning. It is that the bedtime has to move too, and 21:15 feels early on the first few nights.
If you are shifting from a later wake time, move in 15 to 30 minute steps over a week rather than all at once. Light in the first hour after waking helps the body clock follow.
The 6 hour option is there for the nights it cannot be helped, not as a target. Getting enough total sleep matters more than landing exactly on a cycle boundary.
The calculator takes any wake time and any fall-asleep time, and shows the same three options. Free, no signup, runs in your browser.
Open the sleep calculator with 5:00 filled inThese are estimates for general guidance, not medical advice. 90 minutes is an average and your own cycles may run shorter or longer. If sleep problems persist for weeks, please talk to a clinician.