Sleep Cycle Calculator
When to fall asleep (or wake up) to align with 90-minute sleep cycles.
| Cycles | Sleep duration | Go to bed |
|---|---|---|
| 3 | 4.5 hours | 02:16 |
| 4 | 6 hours | 00:46 |
| 5 | 7.5 hours | 23:16 |
| 6 | 9 hours | 21:46 |
Adds a 14-minute buffer for falling asleep. 5-6 cycles is typical for adults.
About this tool
Sleep cycles last roughly 90 minutes. Waking at the end of a cycle leaves you feeling more rested than waking mid-cycle. This tool suggests bedtime / wake times that align cycles, including a ~14-minute fall-asleep buffer.