MySleepMate / How many hours of sleep
The tool
How many hours of sleep is 11pm to 7am?
11pm to 7am is 8 hours in bed. At the 90-minute average cycle length that is five full sleep cycles with about 30 minutes left over, and it sits comfortably above the 7-hour minimum the American Academy of Sleep Medicine recommends for adults. But you will not sleep all eight of those hours. Healthy adults typically take 10 to 20 minutes to fall asleep and wake briefly during the night, so eight hours in bed usually means somewhere around 7 to 7.5 hours actually asleep.
- 11pm → 7am = 8 hours 0 minutes. Five cycles, plus a third of a sixth.
- Above the recommended floor. AASM says 7 or more for adults.
- Time in bed ≠ time asleep. Subtract roughly 20–40 minutes.
- Cycles are the better unit, but they are an average, not a clock.
Eight hours, and about five and a third sleep cycles, which is the more useful number. Below is a calculator for any two times you like, a table of the pairs people actually search for, and the one correction almost every page like this leaves out: what you are measuring here is time in bed, not time asleep.
Third-year medical student at Manipal Tata Medical College, writing about sleep research. A student, not yet a licensed clinician, so everything here is sourced, and none of it is medical advice. Why you should or should not trust me →
Published 2026-08-31 · Last reviewed 2026-08-31 by Chaitanya Banerjee
Researched against primary sources, drafted with AI assistance, then reviewed and approved by the named author. How we write · Corrections log
Work out any two times
Set a bedtime and a wake-up time. The calculator handles times that cross midnight, which is most of them.
8 hours 0 minutes in bed
That is 5 full 90-minute cycles with 30 minutes left over, and it is comfortably above the 7-hour minimum recommended for adults.
Allowing 10–20 minutes to fall asleep, expect roughly 7 hours 35 minutes actually asleep.
Every "hours between two times" tool on the internet, including this one, is doing subtraction. The arithmetic is not the hard part. What matters is that the answer describes time in bed, and the thing that affects you is time asleep, which is shorter, by an amount nobody can calculate for you. I would rather say that plainly than hand you a precise-looking number and let you assume it means more than it does.
The pairs people actually search for
Bedtime to wake-up, with the cycle count and how each one sits against the 7-hour adult minimum. Cycles are calculated at the 90-minute average; the real spread is 70 to 120 minutes, which is why the column says "about".
| Bedtime | Wake-up | Time in bed | About how many cycles | Against the 7-hour floor |
|---|---|---|---|---|
| 9:00 pm | 5:00 am | 8 hours | 5 and a third | Above |
| 9:00 pm | 6:00 am | 9 hours | 6 | Above |
| 10:00 pm | 5:00 am | 7 hours | 4 and two thirds | At the floor |
| 10:00 pm | 6:00 am | 8 hours | 5 and a third | Above |
| 10:00 pm | 7:00 am | 9 hours | 6 | Above |
| 10:30 pm | 6:30 am | 8 hours | 5 and a third | Above |
| 11:00 pm | 5:00 am | 6 hours | 4 | Below |
| 11:00 pm | 6:00 am | 7 hours | 4 and two thirds | At the floor |
| 11:00 pm | 6:30 am | 7 hours 30 minutes | 5 exactly | Above |
| 11:00 pm | 7:00 am | 8 hours | 5 and a third | Above |
| 11:00 pm | 8:00 am | 9 hours | 6 | Above |
| 11:30 pm | 6:30 am | 7 hours | 4 and two thirds | At the floor |
| 11:30 pm | 7:30 am | 8 hours | 5 and a third | Above |
| 12:00 am | 6:00 am | 6 hours | 4 | Below |
| 12:00 am | 7:00 am | 7 hours | 4 and two thirds | At the floor |
| 12:00 am | 7:30 am | 7 hours 30 minutes | 5 exactly | Above |
| 12:00 am | 8:00 am | 8 hours | 5 and a third | Above |
| 1:00 am | 7:00 am | 6 hours | 4 | Below |
| 1:00 am | 8:00 am | 7 hours | 4 and two thirds | At the floor |
| 1:00 am | 9:00 am | 8 hours | 5 and a third | Above |
| 2:00 am | 8:00 am | 6 hours | 4 | Below |
| 2:00 am | 10:00 am | 8 hours | 5 and a third | Above |
Two patterns are worth noticing in that table. The schedules that land on a whole number of cycles, 11pm to 6:30am, midnight to 7:30am, are the 7 hours 30 minutes ones, which is the arithmetic behind every "sleep in multiples of 90 minutes" article you have read. And a 6-hour night, however tidy four cycles sounds, sits below the recommended minimum every time.
Where the 7-hour figure comes from
The comparison column above is not my opinion. It comes from the 2015 joint consensus statement of the American Academy of Sleep Medicine and the Sleep Research Society, published in the Journal of Clinical Sleep Medicine, which recommends that adults sleep 7 or more hours per night on a regular basis to promote optimal health.
Note the shape of that recommendation. It is a floor, not a target, and it is seven rather than the eight almost everybody repeats. If you have spent years believing that anything under eight hours is a failure, that belief does not trace back to the American consensus panel. I went looking, and eight is simply not in it.
The same applies to the cycle column. Ninety minutes is a real average from real research, but it was published alongside a range of roughly 70 to 120 minutes, and the first cycle of your night is usually the shortest. Counting cycles is a useful habit; treating them as fixed 90-minute blocks is where it goes wrong.
Time in bed is not time asleep
This is the part these pages usually skip, and it is the part that changes the answer.
Getting into bed at 11pm does not mean falling asleep at 11pm. Healthy adults typically take somewhere between 10 and 20 minutes to fall asleep, and briefly wake several times during the night without remembering it. Sleep scientists express this as sleep efficiency, time asleep divided by time in bed, and something in the region of 85 to 90 percent is normal for a healthy adult.
I have a number of my own for the first half of that. In a 28-night self-tracking diary run from 1 to 28 February 2026, my estimated sleep latency had a median of 12 minutes, with 50% of observations between 7 and 19 minutes, a 90th percentile of 31 and a worst night of 47. It is one person, self-estimated rather than measured, and it is still more than most pages on this subject can tell you. The full distribution, and what moved it, is on the nap calculator.
So 11pm to 7am is 8 hours in bed and, for most people, somewhere around 7 to 7.5 hours of actual sleep. Still above the recommended floor, comfortably. But if you are scheduling exactly seven hours in bed and wondering why you feel short, this is why: seven hours in bed is not seven hours of sleep, and the gap is usually 30 to 60 minutes.
Build in the difference rather than trying to calculate it. If you need 7 hours of sleep, give yourself 7 hours 30 minutes to 8 hours in bed. That is a padding rule, not a measurement, and I would rather label it as one than dress it up with a decimal point.
Questions people actually ask
How many hours of sleep is 11pm to 7am?
Eight hours in bed. At the 90-minute average that is five full sleep cycles with about 30 minutes left over, and it is above the 7-hour minimum the American Academy of Sleep Medicine recommends for adults. Allowing 10 to 20 minutes to fall asleep, expect roughly 7 to 7.5 hours actually asleep.
How many hours of sleep is 10pm to 6am?
Eight hours in bed, the same as 11pm to 7am, about five and a third 90-minute cycles, and above the recommended 7-hour floor.
How many hours of sleep is 12am to 7am?
Seven hours in bed, or about four and two thirds cycles. That sits exactly at the AASM minimum for adults, which means once you subtract the time it takes to fall asleep you are likely a little under seven hours of actual sleep.
How many hours of sleep is 11pm to 6am?
Seven hours in bed, roughly four and two thirds 90-minute cycles. It meets the 7-hour recommendation on paper, but time in bed is not time asleep, so your actual sleep will usually be closer to 6 to 6.5 hours.
Is 6 hours of sleep enough?
Not for most adults. The 2015 AASM and Sleep Research Society consensus statement recommends 7 or more hours per night, and the accompanying methodology paper is explicit that regularly sleeping less than 7 hours is associated with adverse health outcomes. Six hours is four complete 90-minute cycles, which is tidy arithmetic but still below the recommended floor.
How many sleep cycles is 8 hours?
About five and a third, using the 90-minute average. But cycle length varies from roughly 70 to 120 minutes between people and across a single night, with the first cycle usually the shortest, so treat that as an approximation rather than a count.
Work backwards instead
If you know when you have to get up and want the bedtimes that fit, the main calculator counts backwards from your wake-up time and prints every assumption it makes on the page.
Open the sleep calculator