Wake times
If your alarm is set for 7:30am, when should you go to bed?
Half seven belongs to people with a short commute and a nine o clock start. It is the last alarm on the clock that still counts as a normal working morning, and the first one where a midnight bedtime nearly adds up.
In short
To wake up at 7:30am feeling like you finished a cycle rather than got cut off inside one, go to bed at 11:45pm. 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 10:15pm you get 9h, and 1:15am still leaves you 6h.
- Lights out for a full night
- 11:45pmLights 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 | 10:15pm | 9h | A long night. Worth aiming at if you are paying back sleep debt or training hard. |
| 5 | 11:45pmAim here | 7h 30m | The target most adults should hold on a normal week. |
| 4 | 1:15am | 6h | Short, but a whole number of cycles, so you surface from a lighter patch. |
| 3 | 2:45am | 4h 30m | An emergency night. Fine occasionally, damaging as a pattern. |
A midnight bedtime almost works at this hour
Five cycles before a 7:30 alarm means lights out at 11:45pm, which is the first point on this list where the intended bedtime and the real one might actually be the same number. That alone makes 7:30 easier to keep than 6:30, regardless of chronotype.
The trade is the morning. Half seven with a nine o clock start leaves very little room, so this schedule works best when the commute is short or absent, and falls apart the moment it is not.
- Five cycles: bed at 11:45pm
- Six cycles: bed at 10:15pm
- This is the latest weekday alarm that still leaves an unhurried morning for most people
Later is not the same as more
Moving an alarm from 6:30 to 7:30 only gains you an hour if the bedtime stays where it was. Most people who make that move also drift an hour later at night, end up with the same duration, and then wonder why they do not feel any better.
If the goal is more sleep rather than a later morning, hold the bedtime and move the alarm. If the goal is a later morning because your body clock genuinely runs late, move both and stop fighting it.
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 7:30amyou 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 7:30am 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,7:30am 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 7:30am?
11:45pm for five cycles, 10:15pm for six. Both include roughly fifteen minutes of falling asleep, so the phone needs to be down a little before that.
Is 7:30am too late to wake up on a weekday?
Not if it fits your start time. There is nothing virtuous about an earlier number on the clock. What matters is whether the wake time is consistent and whether the night in front of it is long enough.
I set a 7:30 alarm but wake at 6:45 anyway. Why?
Your body clock is probably running earlier than your schedule, which is common in early chronotypes and increasingly common with age. If you feel fine at 6:45, the honest answer is to move the alarm rather than lie there waiting for it.
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 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.
- AlternativesTock vs Apple Health SleepIf you wear an Apple Watch and you only want to see how long you slept, Apple Health already does it for free and does it better than any phone estimate. Tock adds the room: sound, snoring, a score, an alarm that can move earlier, and a coach that can explain what it found.
- 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 1:00amWhere to put the alarm after a 1:00am lights-out.
- Sleep by ageHow much sleep school-age children needThe American Academy of Sleep Medicine recommends that children aged 6 to 12 years sleep 9 to 12 hours per 24 hours on a regular basis. By this age sleep has consolidated into the night, so the figure is effectively a nightly one and the bedtime has to be counted backwards from the school run.
- NapsThe coffee napA coffee nap means drinking caffeine and then immediately napping for about 20 minutes. Caffeine takes roughly 20 to 30 minutes to have a noticeable effect, so it does not stop you falling asleep quickly, and you wake as it takes hold. The two effects add rather than cancel.
- Wake tonesMusic boxMusic box is Tock's slowest and most nostalgic wake tone, a thin bell-like melody that unwinds instead of alerting. It rings reliably through silent mode because Tock's alarms run on Apple's AlarmKit, but as a tone it is the weakest choice in the set for anyone who genuinely sleeps hard.
An alarm at 7:30am does not have to feel like 7:30am
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.