Enter your wake time and the minimum sleep you want, and you'll get three bedtime candidates — minimum, recommended, and with room for recovery — built around 90-minute cycles. Example: for a 6 a.m. wake and 7 hours wanted, the recommended bedtime is around 10:45 p.m. The 15-minute fall-asleep buffer is added automatically.
Bedtimes that leave room for 6, 7, or 8 hours of sleep, assuming about 15 minutes to fall asleep. Use the calculator above to adjust the fall-asleep buffer and see minimum, recommended, and extended options for your exact wake time.
| Wake time | Bedtime (6h) | Bedtime (7h) | Bedtime (8h) |
|---|---|---|---|
| 5:00 | 22:45 | 21:45 | 20:45 |
| 5:30 | 23:15 | 22:15 | 21:15 |
| 6:00 | 23:45 | 22:45 | 21:45 |
| 6:30 | 0:15 | 23:15 | 22:15 |
| 7:00 | 0:45 | 23:45 | 22:45 |
| 7:30 | 1:15 | 0:15 | 23:15 |
| 8:00 | 1:45 | 0:45 | 23:45 |
| 8:30 | 2:15 | 1:15 | 0:15 |
| 9:00 | 2:45 | 1:45 | 0:45 |
Six hours is a floor rather than a target — the commonly recommended adult range is 7 to 9 hours. See minimum vs recommended sleep for how the two differ and when a short night actually matters.
Each row works backwards from your wake time. The Recommended row aligns with the adult sleep range commonly cited by public health bodies — around 7 to 9 hours (CDC, AASM).
The Minimum row is a floor that lets you function the next day, but using it night after night tends to lower focus and mood. The Extended row leaves room to repay sleep debt or to recover from illness.
Bedtime works better as a window than a point. Aiming for ±15 minutes around your row is realistic and easier to keep up with.
General guidance only, not medical advice.
Recommended sleep length shifts with age. The figures below summarize the ranges from the American Academy of Sleep Medicine (AASM) and the CDC. Treat them as a starting point — individual needs vary.
| Teens (14–17) | 8–10 hours |
|---|---|
| Young adults (18–25) | 7–9 hours |
| Adults (26–64) | 7–9 hours |
| Older adults (65+) | 7–8 hours |
These reference ranges assume healthy adults. Pregnancy, recovery from illness, and shift work may shift the target.
Minimum is a floor for getting through the next day (around 6 hours). Recommended sits inside the 7–9 hour adult range cited by the CDC and AASM. More recovery is for nights when you need to repay sleep debt or recover from illness. Using Minimum every night is not advised.
Healthy adults usually fall asleep in 10 to 20 minutes, with 15 minutes as a common default. If 30+ minutes happens several nights in a row, set a longer fall-asleep value and move bedtime earlier.
It is an average. Real cycles often run 80 to 110 minutes and shift across the night. Use this tool as a rough plan and allow ±15 minutes of drift.
Six hours is a floor, not a target. The commonly recommended adult range is 7 to 9 hours, and most people slowly build sleep debt on a fixed 6-hour schedule. If short nights are unavoidable this week, plan one or two longer nights mid-week rather than saving everything for the weekend.
Yes. Set the wake time to the afternoon or evening and the same reverse calculation works. Darkening the room and keeping a similar sleep window across shift days makes daytime sleep easier.
No. This is general guidance. If you have chronic insomnia, strong daytime sleepiness, or snoring or breathing pauses noted by others, please speak with a sleep clinic or your physician.