What time should I set my alarm? Waking at the end of a cycle
How to pick an alarm time when you go to bed now or at a set hour, and why odd-looking times can feel better.
By Best Sleep Trackers · Updated October 18, 2026
Going to bed right now? The wake-up calculator works forward from your bedtime, the opposite of the bedtime calculator, which works back from the time you need to be up.
Why the times look odd
Sleep moves through light sleep, deep sleep and REM sleep in repeating cycles, which last about 90 minutes in most adults (NHLBI). Waking near the end of a cycle, when sleep is lighter, tends to feel easier than being pulled out of deep sleep.
Each result is your bedtime, plus the minutes you take to fall asleep, plus whole cycles. That is why you may see 6:14 rather than 6:00. If you usually drop off faster or slower, change that setting and the times shift with it.
How many cycles?
Most adults feel best with five or six cycles, which is roughly 7.5 to 9 hours. The AASM and Sleep Research Society recommend at least 7 hours a night for adults (Watson et al., 2015). Four cycles (6 hours) is a bare minimum for the odd night, not a plan.
Tips
- Treat the result as a window. A few minutes either side is fine; the aim is a sensible time, not a stopwatch.
- Keep your wake-up time steady across the week. It matters more than hitting a perfect cycle every morning.
- Short on time? A nap is a different calculation. Try the nap calculator.
- Want the full background? Read sleep cycles explained.
If you sleep a full night and still wake exhausted, talk to a doctor.
Sources
Related articles
- Adult sleep How to nap well How long to nap, when to nap, and how to avoid waking up groggy.
- Adult sleep Sleep cycles explained (and how accurate the 90-minute rule is) What happens during a night of sleep, what a cycle is, and why 90 minutes is an average rather than a rule.
- Sleep myths Myth: you can catch up on sleep at the weekend What research shows about weekend recovery sleep, and what to do instead.
General information only. This tool gives general sleep information and is not a substitute for medical advice. If you're worried about your sleep or your child's, talk to a doctor or pediatrician.