Wake-up calculator
When’s the best time to wake up if you’re going to bed soon? Set your bedtime and the calculator returns wake times that land at the end of a complete 90-minute cycle — so your alarm catches you in light sleep, not deep sleep.
Wake up at one of these times
includes ~14 min to fall asleepMinimum — expect grogginess
Acceptable on short nights
Recommended for most adults
Full restorative sleep
Pick a time at the start of a complete cycle to wake feeling rested, not groggy.
How the wake-up calculator works
Tell it the time you’ll be in bed with the light off. It adds 14 minutes (average sleep latency for healthy adults) for you to actually fall asleep, then walks forward in 90-minute increments. Each wake time you see is at the boundary between cycles, where the body is in light NREM and most likely to wake without sleep inertia.
Why “ending on light sleep” matters more than total hours
A 7-hour night ending at the close of a cycle will usually feel better than an 8-hour night ending in mid-deep-sleep. That isn’t intuitive — most people optimize for “how many hours did I get” — but it’s repeatable in sleep labs. Waking in slow-wave sleep produces a measurable cognitive deficit that lasts 20–40 minutes (the well-named sleep inertia — see Hilditch & McHill, 2019, for a current review).
That said, hours still matter. Below ~6 hours (4 cycles), you’re running a sleep debt no matter how clever the timing is. Sleep below 7 hours night after night is associated with worse cardiovascular outcomes, weight regulation, and immune function in long-running studies. Five cycles is the realistic floor for adults; six is the target.
If you have flexibility on bedtime
Use the bedtime calculator instead — it takes your alarm time as input and tells you when to be in bed. That’s usually the harder constraint anyway: most adults have a fixed wake time and a flexible bedtime, not the other way around.
Frequently asked questions
What time should I wake up if I go to bed at 11 PM?
For 6 cycles (9 hours), wake at 8:14 AM. For 5 cycles (7.5 hours), wake at 6:44 AM. For 4 cycles (6 hours), wake at 5:14 AM. Each option ends at the close of a 90-minute cycle so you wake in light sleep.
What time should I wake up if I go to bed at 10 PM?
For 6 cycles, wake at 7:14 AM. For 5 cycles, wake at 5:44 AM. For 4 cycles, wake at 4:14 AM. Use the calculator above with 22:00 to see all options.
Why do I sometimes wake up before my alarm feeling great?
You woke at the end of a cycle, in light sleep. Your body had completed a clean cycle and the natural rise in cortisol that ends sleep happened to land before your alarm. The whole point of cycle-based wake timing is to engineer that outcome on purpose.
Should I trust my smart alarm app instead?
Smart alarms (Sleep Cycle, Pillow, Apple Watch) try to detect light sleep via motion and wake you in a window around your alarm. They work, but accuracy depends on the device — wrist-based detection is ~70-80% accurate vs polysomnography. A cycle-based calculator and a regular alarm gets you most of the benefit for free.
Does this work for shift workers or night shifts?
Yes — sleep cycles are 90 minutes regardless of when you sleep. The hard part for shift work isn’t cycle timing, it’s the circadian misalignment (sleeping when your body expects to be awake). The calculator still helps you wake at a cycle boundary; pair it with blackout curtains and a consistent sleep window.
What if I add up the cycles and it still seems wrong?
The calculator adds 14 minutes of sleep latency on top of cycles. So "go to bed at 11 PM, 5 cycles" = 14 + 450 = 464 minutes later = 6:44 AM, not 6:30 AM. If you fall asleep faster, subtract a few minutes; slower, add a few.
Common bedtimes
Specific wake times for the most-asked bedtimes: