Bedtimes
You are going to bed at 10:30pm. When should the alarm be?
Half past ten is where a seven o clock alarm stops being generous and starts being exactly enough. Thirty minutes either side of this hour is the difference between a normal morning and a hard one, which is more leverage than half an hour usually has.
In short
If you go to bed at 10:30pm, set your alarm for 6:15am. That is 7h 30m of sleep across 5 full cycles, plus the fifteen minutes it takes most people to actually fall asleep, so you wake at the end of a cycle rather than inside one. 7:45am gives you 9h and 4:45am still leaves you 6h.
- Alarm for a full night
- 6:15amAlarm for a full night5 cycles, 7h 30m asleep
- Length of an average sleep cycle
- 90 minLength of an average sleep cycleReal ones run 70 to 120
- Added before the first cycle
- 0h 15mAdded before the first cycleMost calculators forget this
| Cycles | Set the alarm | Time asleep | What it is good for |
|---|---|---|---|
| 6 | 7:45am | 9h | Nine hours. Worth it if you are paying back debt, and more than most adults need every night. |
| 5 | 6:15amAim here | 7h 30m | The target most adults should hold on a normal week. |
| 4 | 4:45am | 6h | Six hours. Short, but a whole number of cycles, so you surface from a lighter patch. |
| 3 | 3:15am | 4h 30m | An emergency night. Fine occasionally, damaging as a pattern. |
The half hour with the most leverage in the week
From 10:30pm, five full cycles finish at 7:15am. Move the bedtime half an hour later and a 7am alarm cuts into the fifth cycle rather than landing after it. Move it half an hour earlier and you get the whole cycle plus slack. Very little else in a sleep schedule flips that cleanly on thirty minutes.
This is also the hour where most people are genuinely sleepy but not yet tired, which is the window worth using. Pushing past it tends to catch a second wind, because the body clock has a stretch in the late evening where alertness rises before it drops, and getting past that means waiting for it to come round again.
- From 10:30pm, five cycles lands at 7:15am and six at 5:45am
- A 7am alarm here is about eight hours of opportunity, which is enough but not spare
- The late-evening alertness rise is real, and pushing through it usually costs more than the half hour it buys
The second wind is a wake maintenance zone
That burst of energy an hour or two before your usual bedtime has a name. The circadian system produces a stretch of strong wake drive in the late evening, right before it hands over to the melatonin rise, and it is the hardest part of the day to fall asleep in even when you are short on sleep.
The practical version is simple. If you feel sleepy at 10:30 and push through to midnight to finish something, you are not tired-but-productive, you are on the far side of a window that will not reopen for a couple of hours. Going to bed on the first sleepy signal is worth more than any wind-down routine.
The mechanism is at /glossary/wake-maintenance-zone.
The table is an average, and your night is not
Ninety minutes is the number everybody quotes because it is roughly the mean. A real night does not run to it. Your first cycle tends to be short, the middle ones stretch, and by the last couple of hours you are cycling faster with more of each one spent in light sleep and REM. So the arithmetic above gets you to approximately the right alarm, and then the last half hour is a coin toss.
That coin toss is the entire argument for a smart alarm, and it is why this page ends with one rather than with a schedule. Tock spends the thirty minutes before 6:15am watching for the moment you are already stirring, on two channels: movement from the accelerometer and sound from the microphone. When it finds one it rings a little early. When it does not,6:15am rings exactly as you set it, so the fallback is never worse than a normal alarm. You can read the mechanism at how smart wake works, or start with sleep cycles explained if the arithmetic itself is the part you want to understand properly.
Questions people ask
If I go to sleep at 10:30pm what time should I wake up?
Five sleep cycles puts the alarm at 7:15am for seven and a half hours of sleep. Six cycles is 5:45am at nine hours and four is 8:45am at six. Each figure includes the roughly fifteen minutes it takes to fall asleep after lights out.
Is 10:30pm a good time to go to bed?
For a standard working morning, yes. It clears eight hours of opportunity for any alarm from 6:45am, it is late enough to have an evening, and it sits close to when most adults naturally get sleepy. It is only tight if your alarm is before 6:30.
How much sleep is 10:30pm to 6:30am?
Eight hours in bed and about seven and three quarter hours asleep. That lands between five and six full cycles, so the alarm can catch you in the middle of one, which is why the morning sometimes feels worse than the total suggests.
Other bedtimes
The same arithmetic, run from a different lights-out.
- Going to bed at 8:00pmWhere to put the alarm after a 8:00pm lights-out.
- Going to bed at 8:30pmWhere to put the alarm after a 8:30pm lights-out.
- Going to bed at 9:00pmWhere to put the alarm after a 9:00pm lights-out.
- Going to bed at 9:30pmWhere to put the alarm after a 9:30pm lights-out.
- Going to bed at 10:00pmWhere to put the alarm after a 10:00pm lights-out.
- Going to bed at 11:00pmWhere to put the alarm after a 11:00pm lights-out.
- Going to bed at 11:30pmWhere to put the alarm after a 11:30pm lights-out.
- Going to bed at 12:00amWhere to put the alarm after a 12:00am lights-out.
- Going to bed at 12:30amWhere to put the alarm after a 12:30am lights-out.
- Going to bed at 1:00amWhere to put the alarm after a 1:00am lights-out.
- Going to bed at 1:30amWhere to put the alarm after a 1:30am lights-out.
- Going to bed at 2:00amWhere to put the alarm after a 2:00am lights-out.
- Going to bed at 3:00amWhere to put the alarm after a 3:00am lights-out.
Elsewhere on the site
A different corner of the same problem.
- Head to headPillow vs SleepScoreIf an Apple Watch is already part of your night, Pillow gets far more out of it than SleepScore can from across the room. If buying a wearable is off the table for you, SleepScore was made for exactly that person.
- FeaturesWind-downWind-down is a short guided routine you run before sleep. It has 6 steps you can reorder or drop, three lengths, and a 30 second drift at the end that hands you over to the good-night screen.
- Sleep soundsWhite noiseWhite noise holds equal power in every one hertz band, which makes it the brightest of the sleep noises and the best at covering thin, sharp sounds: keys in a lock, a running tap, a voice through a wall. That same brightness is why plenty of people last about an hour before switching to pink or brown.
- Tock for youNight owlsYou are wide awake at 1am and useless at 7am, and every piece of advice you have ever read starts with going to bed earlier, which you have done, repeatedly, while staring at the ceiling.
- AlternativesTock vs SleepScoreSleepScore is the better pick if you want breathing and movement read contactlessly by a method you can have explained to you, and you already have an alarm you trust. Tock is the pick if you want one app that both tracks the night and wakes you, with playable audio of what it heard.
- RoundupsThe best smart alarm apps, and what smart should meanTock is the best smart alarm app on iPhone. It watches the 30 minutes before your alarm using two signals, movement and sound, rings early if it catches a lighter moment, and falls back to your set time no matter what. Sleep Cycle is the long-established alternative, and Pillow is the better pick if you already wear an Apple Watch to bed.
Tomorrow, you wake up just before your alarm
Setting the alarm on a cycle boundary is arithmetic and your night is not. Tock watches the half hour before 6:15am for a lighter moment and rings then, and your set time is always the fallback.