Calculate the best bedtimes and wake-up times based on 90-minute sleep cycles to wake up feeling refreshed.
| Go to Sleep At | Sleep Duration | Cycles | Quality |
|---|---|---|---|
| 9:16 PM | 9h 0m | 6 | Optimal (9h) |
| 10:46 PM | 7h 30m | 5 | Great (7.5h) |
| 12:16 AM | 6h 0m | 4 | Good (6h) |
| 1:46 AM | 4h 30m | 3 | Minimum (4.5h) |
| 3:16 AM | 3h 0m | 2 | Poor (3h) |
* Assumes ~14 minutes to fall asleep. Times based on 90-minute sleep cycles.
| Wake Up At | Sleep | Quality |
|---|---|---|
| 6:13 AM | 9h 0m | Optimal (9h) |
| 4:43 AM | 7h 30m | Great (7.5h) |
| 3:13 AM | 6h 0m | Good (6h) |
| 1:43 AM | 4h 30m | Minimum (4.5h) |
| 12:13 AM | 3h 0m | Poor (3h) |
| Age Group | Recommended Sleep |
|---|---|
| Newborn (0–3 mo) | 14–17 hours |
| Infant (4–11 mo) | 12–15 hours |
| Toddler (1–2 yr) | 11–14 hours |
| Preschool (3–5 yr) | 10–13 hours |
| School age (6–13) | 9–11 hours |
| Teen (14–17) | 8–10 hours |
| Young adult (18–25) | 7–9 hours |
| Adult (26–64) | 7–9 hours |
| Older adult (65+) | 7–8 hours |
Find your optimal bedtime or wake-up time with our free sleep calculator, based on 90-minute sleep cycles, so you wake up feeling more rested instead of mid-cycle groggy.
Sleep occurs in cycles of roughly 90 minutes each. Waking up at the end of a full cycle tends to leave you feeling more refreshed. This calculator works backward or forward in 90-minute increments, plus a buffer to fall asleep.
Sleep research shows the average complete sleep cycle lasts approximately 90 minutes, though this can vary somewhat by individual.
Most adults benefit from 5-6 full cycles per night (7.5-9 hours), though individual sleep needs vary.
Yes, this calculator typically adds a buffer (often around 15 minutes) for the time it takes to actually fall asleep.
It's not harmful, but it commonly causes grogginess (sleep inertia).