Sleep & wake-up
Wake up time calculator
If you go to sleep now, here are the best times to set your alarm so you wake at the end of a sleep cycle.
Highlighted times are 5–6 estimated cycles, a common target for adults. Cycle length varies, so shift the time if you still wake up groggy.
How wake-up times are calculated
Sleep runs in cycles of roughly 90 minutes, moving from light sleep to deep sleep and then to REM. Waking at the end of a cycle, when sleep is lightest, usually feels easier than being pulled out of deep sleep by an alarm. This tool adds about 15 minutes to fall asleep, then counts forward in 90-minute cycles from now, so each suggested time lands near the estimated end of a cycle.
| Cycles | Sleep length | Good for |
|---|---|---|
| 3 cycles | 4.5 hours | A short night or emergency |
| 4 cycles | 6 hours | A light but workable night |
| 5 cycles | 7.5 hours | A solid night for most adults |
| 6 cycles | 9 hours | Full recovery or catching up |
Getting the most from it
Treat these times as guides, not exact science, because cycle length varies from person to person and night to night. Pick the latest time that still gives you 5 or 6 cycles, keep your room dark and cool, and try to wake at the same time each day. A consistent wake time does more for how rested you feel than any single alarm.
Frequently asked questions
Why 90-minute cycles?
A full sleep cycle averages about 90 minutes, cycling through light, deep and REM sleep. Waking at the end of one, rather than in the middle of deep sleep, is why some wake times feel easier than others.
How many cycles should I aim for?
Most adults do best with 5 to 6 cycles, which is roughly 7.5 to 9 hours. Fewer than 5 leaves many people short on sleep, so use the shorter options only when you have no choice.
Why add 15 minutes before the first cycle?
Few people fall asleep the instant their head hits the pillow. Adding about 15 minutes for falling asleep makes the wake times more realistic than counting from the moment you lie down.