Sleep & wake-up
Alarm time calculator
Enter when you fall asleep and get alarm times that land at the end of a sleep cycle, not the middle.
Each option is the estimated end of an average 90-minute cycle; real cycles vary. Waking in lighter sleep tends to feel easier than waking from deep sleep.
Why set your alarm to a sleep cycle
Sleep is not one long flat state. You move through cycles of about 90 minutes, each running from light sleep down into deep sleep and back up through dream sleep. Being woken in the middle of deep sleep is what causes that drugged, heavy feeling in the morning. Setting your alarm to the end of a cycle, when sleep is lighter, tends to make getting up noticeably easier. This calculator takes the time you fall asleep, adds a short buffer for drifting off, and lists the cycle-aligned wake times.
| Cycles | Approx. sleep | Suits |
|---|---|---|
| 4 | About 6 hours | A short night when time is tight |
| 5 | About 7.5 hours | A solid target for most adults |
| 6 | About 9 hours | Full recovery or catching up |
Making it work
Pick the latest option that still fits your morning, and favour one that gives you five or six cycles so total sleep stays healthy. The times assume roughly 15 minutes to fall asleep; if you tend to drop off faster or slower, nudge your bedtime rather than the alarm. The biggest gains come from keeping the same wake time every day, which strengthens your body clock and makes the alarm feel less like a shock over time.
Frequently asked questions
How does the alarm time calculator work?
It takes the time you fall asleep, adds about 15 minutes to drift off, then adds full 90-minute cycles. Each suggested alarm aims for the end of an average 90-minute cycle, when sleep is usually lighter.
Which alarm time should I choose?
Pick the one that gives you enough total sleep and still fits your morning. Five or six cycles, around 7.5 to 9 hours, suits most adults. The marked options are the stronger choices.
Why do I still feel tired at a cycle-aligned time?
Cycle length varies night to night and person to person, so the timing is an estimate. Total sleep and a consistent schedule matter more, so make sure you are getting enough hours overall.