Wake times
If your alarm is set for 4:00am, when should you go to bed?
Four in the morning is not early. It is late at night with a job attached. Almost nobody has a body clock that wants this hour, which is why a 4am alarm has to be planned backwards from bedtime rather than bolted onto a normal evening.
In short
To wake up at 4:00am feeling like you finished a cycle rather than got cut off inside one, go to bed at 8:15pm. That is 7h 30m of sleep across 5 full cycles, plus the fifteen minutes it takes most people to drop off. If you can get to bed at 6:45pm you get 9h, and 9:45pm still leaves you 6h.
- Lights out for a full night
- 8:15pmLights out 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 for falling asleep
- 0h 15mAdded for falling asleepMost calculators forget this
| Cycles | Lights out | Time asleep | What it is good for |
|---|---|---|---|
| 6 | 6:45pm | 9h | A long night. Worth aiming at if you are paying back sleep debt or training hard. |
| 5 | 8:15pmAim here | 7h 30m | The target most adults should hold on a normal week. |
| 4 | 9:45pm | 6h | Short, but a whole number of cycles, so you surface from a lighter patch. |
| 3 | 11:15pm | 4h 30m | An emergency night. Fine occasionally, damaging as a pattern. |
Nobody drifts into a 4am wake up by accident
The people who set this alarm are doing it for a reason they did not choose. Bakers, long-haul crew, market traders on the wrong side of an ocean, gym staff who open the doors at five, anyone catching the first flight of the day. It is a working hour, not a lifestyle.
That matters because the advice for a 4am start is different from the advice for a 6am start. At 6am you can nudge your evening earlier and your body will meet you halfway. At 4am you are asking to fall asleep while the sun is still up for half the year, and no amount of willpower changes what light does to melatonin.
- A 7:30pm bedtime is the price of eight hours, and that is a real social cost, not a scheduling detail
- Blackout in the bedroom stops being optional in summer
- Anchoring the wake time seven days a week is easier than flipping between 4am and 9am on days off
Protect the front of the night, not the back
When your wake time is fixed at 4am, the only variable left is when you fall asleep, and the only lever on that is the ninety minutes before bed. Dim the room, get off the screen, and do the same three things in the same order every night so your body starts the descent before you lie down.
Tock is useful here mostly because it takes the last thirty minutes off your hands. The wind-down runs its steps, the good-night screen dims itself to near black after twenty seconds so the phone stops being a light source, and the alarm still rings at 4am through silent mode and a Focus.
If you are on this schedule because of shift work rather than choice, the persona page for night shift workers is the more useful read.
The table is an average, and your night is not
Ninety minutes is the number everyone quotes because it is the mean. In a real night your first cycle tends to run short, the middle ones stretch, and by the last hour before 4:00amyou are cycling faster and spending more of it in light sleep and REM. So the table gets you to roughly the right bedtime, and then the last half hour is a coin toss.
That last half hour is the entire argument for a smart alarm. Tock watches the thirty minutes before 4:00am on two channels, movement from the accelerometer and sound from the microphone, and rings a little early if it finds a lighter moment. If it does not find one,4:00am rings exactly as you set it. You can read more inhow smart wake works, or start withsleep cycles explained if the arithmetic above is the part you want to understand properly.
Questions people ask
What time should I go to bed to wake up at 4am?
For six full sleep cycles, around nine hours including the time it takes to drop off, go to bed at 6:45pm. Five cycles puts you at 8:15pm, which is roughly seven and a half hours and the most realistic target for most people on this schedule.
Is waking up at 4am bad for you?
The hour itself is not the problem. The problem is the sleep you lose when a 4am alarm sits on top of a normal evening. If you consistently get seven hours before it, a 4am wake time is survivable. If it is costing you two hours a night, that debt accumulates and no morning routine offsets it.
How do I fall asleep at 7pm when it is still light outside?
Blackout blinds or a proper sleep mask, and dim everything indoors for the ninety minutes before bed. Light in the evening is the single biggest input to when your body releases melatonin, and it beats every other trick on the list.
Other wake times
The same maths, run for a different alarm.
- Waking up at 4:30amBedtimes by sleep cycle for a 4:30am alarm.
- Waking up at 5:00amBedtimes by sleep cycle for a 5:00am alarm.
- Waking up at 5:30amBedtimes by sleep cycle for a 5:30am alarm.
- Waking up at 6:00amBedtimes by sleep cycle for a 6:00am alarm.
- Waking up at 6:30amBedtimes by sleep cycle for a 6:30am alarm.
- Waking up at 7:00amBedtimes by sleep cycle for a 7:00am alarm.
- Waking up at 7:30amBedtimes by sleep cycle for a 7:30am alarm.
- Waking up at 8:00amBedtimes by sleep cycle for a 8:00am alarm.
- Waking up at 8:30amBedtimes by sleep cycle for a 8:30am alarm.
- Waking up at 9:00amBedtimes by sleep cycle for a 9:00am alarm.
Elsewhere on the site
A different corner of the same problem.
- Sleep by ageHow much sleep older adults needThe American Academy of Sleep Medicine recommendation of 7 or more hours per night applies to adults without an upper age cut-off. What changes with age is not how much sleep is needed but how easily it is obtained: the night becomes lighter, more broken, and shifts earlier.
- NapsThe 90 minute napA 90 minute nap is approximately one full sleep cycle, which means it ends in a lighter stage rather than in slow wave sleep. That produces much less grogginess than a 30 or 60 minute nap, and it includes both the deep sleep and the REM that shorter naps miss.
- Wake tonesGentle alarm soundsA gentle alarm works when it catches you at a light moment and fails when it lands in the heaviest part of your night, which is a timing problem rather than a volume one. Tock watches movement and sound across the 30 minutes before your alarm and rings early at a lighter moment if it finds one, with your set time as the fallback.
- Head to headApple Health Sleep vs Sleep CycleIf you wear an Apple Watch to bed, Apple's built-in tracking is more accurate and costs nothing, so Sleep Cycle has to win on the alarm and the sound library instead. If you don't own a Watch, Sleep Cycle is the only one of the two that records anything.
- 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.
An alarm at 4:00am does not have to feel like 4:00am
Tock watches the half hour before your alarm and rings a little early if it finds a lighter moment. Your set time is always the fallback, so you are never late.