Counting forward from 4:00 AM
Going to bed at 4:00 AM and falling asleep about 15 minutes later means your first sleep cycle starts at 4:15 AM. With cycles of roughly 90 minutes, they end at:
- 10:15 AM (10:15) after four cycles, or 6 hours asleep;
- 11:45 AM (11:45) after five cycles, or 7.5 hours;
- 1:15 PM (13:15) after six cycles, or 9 hours.
Which wake-up time fits a 4 AM bedtime?
11:45 AM gives 7.5 hours of sleep, meeting the recommendation that adults sleep at least 7 hours, and still leaves most of the afternoon.
1:15 PM gives 9 hours. It fits a night-shift routine or a day when you have nothing planned until the afternoon.
10:15 AM gives 6 hours. It will get you through one day, but it is not enough to rely on.
If you take more or less than 15 minutes to fall asleep
These times assume you fall asleep within 15 minutes. If it takes you longer, every wake-up time moves later by the difference. The highlighted row matches the times at the top of this page.
| Fall asleep in | 9 h | 7.5 h | 6 h |
|---|---|---|---|
| 5 min | 1:05 PM13:05 | 11:35 AM11:35 | 10:05 AM10:05 |
| 10 min | 1:10 PM13:10 | 11:40 AM11:40 | 10:10 AM10:10 |
| 15 min | 1:15 PM13:15 | 11:45 AM11:45 | 10:15 AM10:15 |
| 20 min | 1:20 PM13:20 | 11:50 AM11:50 | 10:20 AM10:20 |
| 30 min | 1:30 PM13:30 | 12:00 PM12:00 | 10:30 AM10:30 |
Making daytime sleep work
Sleeping after sunrise is harder than sleeping at night, because daylight and noise tell your body clock it is time to be awake. A few changes make a real difference:
- Use blackout curtains or an eye mask, and earplugs or a fan for steady background noise.
- Put your phone on silent and let others in your home know when you are sleeping.
- Keep the bedroom cool, as it usually warms up during the day.
- On the way home after a night shift, some people find sunglasses help them feel less wide awake.
- Avoid caffeine in the last few hours before your planned bedtime.
Getting back to a normal bedtime
If 4:00 AM was unusual for you, get up at one of the times above, get some daylight early in your day, and go to bed at your usual time that night, even if you are not very sleepy. Your body clock usually catches up within a night or two.
Caffeine and naps after a 4 AM night
If you need a boost the next day, keep coffee and tea to the early part of your day so it doesn’t keep you awake that night. A short nap of 10–20 minutes can help, but avoid long or late naps.
More answers
- Wake-up time if you sleep at 3 AMNearby answer
- Wake-up time if you sleep at 5 AMNearby answer
- Wake-up time if you sleep at 2 AMNearby answer
- Bedtime for a 4 AM wake-upRelated answer
- Bedtime for a 4:15 AM wake-upRelated answer
- Bedtime for a 4:30 AM wake-upRelated answer
- Bedtime for a 4:45 AM wake-upRelated answer
Frequently asked questions
How much sleep do I get if I go to bed at 4 AM and wake at 10 AM?
About 5 hours 45 minutes, if you fall asleep by 4:15 AM. That is below the adult minimum of 7 hours. Waking at 10:15 AM (10:15) lines up with the end of a cycle.
Is a 4 AM bedtime OK for night-shift workers?
It can be, if you get 7 or more hours and keep your schedule as regular as possible. A dark, quiet bedroom makes daytime sleep much easier.
Why do I wake up early after going to bed at 4 AM?
Daylight, traffic and household noise are common causes, along with your body clock expecting you to be awake. Blackout curtains, earplugs and a cooler room can help.
Related calculators
Wake-up time calculator
Going to bed now or at a set time? Find wake-up times that land at the end of a cycle.
Bedtime calculator
Enter any wake-up time to see bedtimes that let you wake between sleep cycles.
Nap calculator
Plan a 10-, 20- or 90-minute nap and see when to set your alarm.
Sleep debt calculator
Add up the last seven nights and see how far you are from your sleep target.
Sources
- National Institute of Neurological Disorders and Stroke. Brain Basics: Understanding Sleep.
- National Heart, Lung, and Blood Institute. How Sleep Works.
- Watson NF, et al. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Journal of Clinical Sleep Medicine, 2015;11(6):591–592. doi:10.5664/jcsm.4758.
- Centers for Disease Control and Prevention. About Sleep.
When to seek help
Talk to a doctor if you:
- regularly take longer than 30 minutes to fall asleep, or wake in the night and can’t get back to sleep;
- snore loudly, or someone notices you gasp or stop breathing while asleep;
- feel very sleepy during the day, especially while driving or working, despite enough time in bed.