Bedtimes
You are going to bed at 9:00pm. When should the alarm be?
Nine is the earliest bedtime that a normal adult life will tolerate. It leaves an evening, it fits a 5am or 6am start with real sleep underneath it, and unlike anything earlier, most people can actually fall asleep at it.
In short
If you go to bed at 9:00pm, set your alarm for 4:45am. 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. 6:15am gives you 9h and 3:15am still leaves you 6h.
- Alarm for a full night
- 4:45amAlarm 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 | 6:15am | 9h | Nine hours. Worth it if you are paying back debt, and more than most adults need every night. |
| 5 | 4:45amAim here | 7h 30m | The target most adults should hold on a normal week. |
| 4 | 3:15am | 6h | Six hours. Short, but a whole number of cycles, so you surface from a lighter patch. |
| 3 | 1:45am | 4h 30m | An emergency night. Fine occasionally, damaging as a pattern. |
The practical floor for an early schedule
There is a reason 9pm shows up so often in advice about early rising and 8pm almost never does. Nine is roughly where a moderately early chronotype starts producing melatonin, so the light going off and the body being ready line up rather than fighting. Any earlier and most people are lying in the dark waiting.
It is also the bedtime that makes a 6am alarm generous rather than tight. Five cycles from nine is 5:45am, so a 6am wake time gives you the full seven and a half hours plus a little slack, which is the shape of a schedule that survives a bad night without collapsing.
- From 9pm, five cycles lands at 5:45am and six at 4:15am
- A 6am alarm on a 9pm bedtime is the most forgiving early schedule there is
- It is the bedtime most likely to still be there in three months, which matters more than the arithmetic
The alarm is the part worth changing, not the bedtime
If you are already at 9pm and mornings still hurt, the bedtime is probably not the problem. Waking badly is usually about which part of a cycle the alarm interrupts rather than how much sleep came before it. Being pulled out of deep sleep at 5:45am after seven and a half hours feels worse than surfacing naturally at 5:52am after seven and a half hours and eight minutes.
That gap is what a smart alarm is for. Tock watches the half hour before your alarm on two channels, movement from the accelerometer and sound from the microphone, and rings a little early when it finds a lighter moment. If it never finds one, your set time rings exactly as you left it.
The mechanism is written out at /features/smart-wake, and what sleep inertia actually is at /guides/what-is-sleep-inertia.
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 4:45am 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,4:45am 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
What time should I wake up if I go to sleep at 9pm?
Five cycles puts the alarm at 5:45am for seven and a half hours of sleep, which is the target most adults should hold. Six cycles is 4:15am at nine hours, and four is 7:15am. All three include fifteen minutes to fall asleep.
Is 9pm a good bedtime for adults?
It is a good bedtime if your morning starts early. Nine hours of opportunity before a 6am alarm is comfortable rather than tight, and 9pm is late enough that most people fall asleep rather than lie there. If your morning starts at eight, 9pm will usually leave you awake at 4am with nowhere to go.
How many hours of sleep do I get if I sleep at 9pm and wake at 6am?
Around eight hours and forty five minutes, once you take off the fifteen minutes or so it takes most people to actually fall asleep. That is closer to six full cycles than five, so a 6am alarm on a 9pm bedtime is a generous night rather than a tight one.
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 9:30pmWhere 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 10:30pmWhere to put the alarm after a 10:30pm 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.
- NapsThe 10 minute napA 10 minute nap lifts alertness without taking you into slow wave sleep, so you wake up clear rather than groggy. It is the safest nap to take close to work or driving, and it does nothing for memory consolidation, which needs considerably longer.
- Wake tonesBeaconBeacon is a wake tone in Tock: an evenly spaced two-note pulse that your ear identifies as an alarm almost immediately. Tock's alarms are built on Apple's AlarmKit, so Beacon rings on the native full-screen alert even when the phone is on silent, sitting in a Focus, or the app hasn't been opened since last night.
- Head to headSleep Cycle vs SleepScoreIf you want one app that watches the night and also rings in the morning, Sleep Cycle. If you only want the measurement, and you want the method explained rather than asserted, SleepScore.
- FeaturesAlarm on silentTock's alarms are registered with iOS through Apple's AlarmKit framework rather than played by the app in the background. That is why they ring with the ringer off, through a Focus, with Tock closed, on the native full-screen alert.
- Sleep soundsSleeper trainA sleeper train bed is a low broadband rumble with a slow, regular rail rhythm over it and the closed-in quality of a cabin, and that combination masks well while giving your attention something gentle to rest on. The rhythm is also the catch: a regular pattern is something you can start tracking again if you surface at 3am.
- Tock for youTravellers with jet lagYou landed, you are on local time on paper, and your body is running four or eight hours behind. Wide awake at 3am, unusable at 3pm, and it lasts roughly a day per time zone.
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 4:45am for a lighter moment and rings then, and your set time is always the fallback.