Wake Up Time Calculator
Find the best times to wake up based on your bedtime, using 90-minute sleep cycles.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter your bedtime to see suggested wake-up times based on 90-minute sleep cycles.
Use 24-hour HH:MM format, e.g. 23:00 or 22:30.
Your result
06:45
5 cycles (7.5 hours)
3 cycles (4.5 hours)03:45
4 cycles (6 hours)05:15
6 cycles (9 hours)08:15
AI explanation
Formula
Wake time = bedtime + minutes to fall asleep + (90 minutes × number of sleep cycles)Worked example
Bedtime 23:00, 15 minutes to fall asleep
| Field | Value |
|---|---|
| Bedtime (24-hour) | 23:00 |
| Minutes to fall asleep | 15 |
| 3 cycles (4.5 hours) | 03:45 |
| 4 cycles (6 hours) | 05:15 |
| 5 cycles (7.5 hours) | 06:45 |
| 6 cycles (9 hours) | 08:15 |
Assumptions
- Assumes an average sleep cycle length of 90 minutes, a commonly cited approximation — actual individual cycle length varies.
- Waking up at the end of a full cycle (rather than mid-cycle) is generally associated with feeling more rested, though individual results vary.
Frequently asked questions
Why 90-minute cycles?
A full sleep cycle (moving through light sleep, deep sleep, and REM) is commonly estimated at around 90 minutes — waking up at the end of a cycle rather than in the middle of one is widely believed to feel less groggy.
Which option should I pick?
5-6 cycles (7.5-9 hours) is the commonly recommended range for adults, so those options are highlighted, but individual sleep needs vary.
I need to work backward from a wake-up time instead — is there a version for that?
Yes — see the Sleep Time Calculator, which suggests bedtimes based on a target wake-up time.