Wake times
If your alarm is set for 9:00am, when should you go to bed?
Nine in the morning gets treated as a confession rather than a schedule, and for a lot of people that is unfair. A late body clock is a real trait, it is partly genetic, and telling someone with one to become a morning person is about as useful as telling them to be taller.
In short
To wake up at 9:00am feeling like you finished a cycle rather than got cut off inside one, go to bed at 1:15am. 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 11:45pm you get 9h, and 2:45am still leaves you 6h.
- Lights out for a full night
- 1:15amLights 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 | 11:45pm | 9h | A long night. Worth aiming at if you are paying back sleep debt or training hard. |
| 5 | 1:15amAim here | 7h 30m | The target most adults should hold on a normal week. |
| 4 | 2:45am | 6h | Short, but a whole number of cycles, so you surface from a lighter patch. |
| 3 | 4:15am | 4h 30m | An emergency night. Fine occasionally, damaging as a pattern. |
A late clock is a trait, not a character flaw
Chronotype sits on a spectrum and a meaningful share of the population runs genuinely late. If your natural window is one in the morning to nine, forcing a 6am alarm does not turn you into an early riser. It gives you a permanent three hour sleep deficit and a worse mood.
A 9am wake time also shows up for two other reasons that have nothing to do with preference: recovering after a run of night shifts, and the weekend after a week of getting up at six. Both are catch-up sleep, and both are better handled by moving less rather than more.
- Five cycles: bed at 1:15am
- Six cycles: bed at 11:45pm
- Tock's onboarding includes the validated rMEQ questionnaire, which gives you a body-clock result rather than a guess
If you need this to be earlier, move it slowly
A late chronotype can shift, but not by decree. Fifteen minutes earlier at a time, held for four or five days, with bright light immediately on waking and dim light in the evening. Expect the whole move from nine to seven to take a couple of months, and expect it to slide back if you stop the light discipline.
If the schedule works for your life as it is, there is no medical reason to change it. Regularity is worth more than earliness, and a stable 9am beats a chaotic 7am on almost every measure that matters.
If you are sleeping past nine and still exhausted every day, that is worth raising with a doctor rather than solving with an app.
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 9:00amyou 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 9:00am 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,9:00am 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 9am?
1:15am for five cycles, 11:45pm for six. If you are on this schedule by choice rather than necessity, the six cycle option is the one that leaves you feeling best.
Is waking up at 9am unhealthy?
Not in itself. What matters is whether it is consistent and whether you are getting daylight during the day. The health signals people associate with late waking are mostly signals of irregular sleep and low light exposure, and both of those are fixable without moving the alarm.
Can I change my chronotype?
You can shift your schedule, within limits, and the lever is light rather than willpower. Bright light soon after waking pulls the clock earlier, and evening light pushes it later. What you cannot do is turn a late chronotype into an early one permanently, and pretending otherwise is how people end up chronically short of sleep.
Should I set an alarm for 9am at weekends if I get up at 7am on weekdays?
A two hour swing is on the edge. Keeping the weekend wake time within about an hour of the weekday one costs you one lie-in and buys you a much easier Monday. If you need the recovery sleep, take it as an early night on Saturday rather than a late morning on Sunday.
Other wake times
The same maths, run for a different alarm.
- Waking up at 4:00amBedtimes by sleep cycle for a 4:00am 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.
Elsewhere on the site
A different corner of the same problem.
- Sleep soundsCricketsA field of crickets is not one insect but dozens slightly out of phase with each other, and that stagger is what turns a repeating chirp into a steady high shimmer you can drift on. It lives almost entirely above 2 kHz, so it covers thin, sharp sounds well and does nothing whatsoever about traffic.
- Tock for youPeople who hate morningsThe alarm goes off and you feel physically wrong. Not tired exactly, more like you were pulled out of something, and it takes the better part of an hour before you are a person again.
- AlternativesTock vs Sleep as AndroidSleep as Android is Android only, so an iPhone owner cannot have it at any price. Tock is the nearest thing on iOS in spirit: sleep tracking from the phone, a smart wake window, snore detection and a task before the alarm stops. It is not as deep, and it does not talk to your smart bulbs.
- RoundupsThe best white noise apps, and when a fan beats all of themIf you want one sound forever, a hardware noise machine or a cheap fan beats every app here and costs less over two years. If you want to change what you sleep to, layer sounds together and have the same app wake you up in the morning, Tock is the better pick.
- BedtimesGoing to bed at 8:00pmWhere to put the alarm after a 8:00pm lights-out.
- Sleep by ageHow much sleep toddlers needThe American Academy of Sleep Medicine recommends that children aged 1 to 2 years sleep 11 to 14 hours per 24 hours, including naps, on a regular basis. Most of that has consolidated into the night by the second birthday, with one daytime nap doing the rest.
An alarm at 9:00am does not have to feel like 9:00am
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.