Hermione has the Time-Turner in Prisoner of Azkaban and uses it all year to take extra classes. Many times in the book she's exhausted and barely managing all of her studies.

What I never understood is why she didn't simply use the Time-Turner to get more hours in the day to sleep and study more. Since she used it at the end for the escapes, it doesn't seem likely that its use would be monitored, otherwise it wouldn't have been a viable plan. Likewise, since she used it at the drop of a hat it doesn't seem as though there were any restrictions on it in terms of what time one could use it.

So why didn't she just use it to sleep more?

  • 37
    I assumed she was told she could only use it for classes. Far be it for Hermione to break the rules!
    – Liath
    Aug 4, 2014 at 19:29
  • 1
    I rather suspect that Hermione is getting burnt out by work, beyond normal tiredness. I’m not convinced more hours for sleep and study would really help; if anything, they might make it worse.
    – alexwlchan
    Aug 4, 2014 at 19:53
  • 8
    She would age a lot faster if she used it too much. A class or two each week is not much, but working 24 hours and using the time turner to sleep would quickly add up to years.
    – vsz
    Aug 6, 2014 at 4:16
  • 2
    HPMOR has a few good explanations on-topic (with Harry abusing TT in most unobvious ways ), however such kind of fanfiction is not a good example here.
    – kagali-san
    Aug 6, 2014 at 15:06
  • 1
    Because JK often shows the boys sleeping, but never even references that girls need sleep. Maybe witches just don't need it. :)
    – JMD
    Aug 6, 2014 at 18:08

7 Answers 7


“It’s called a Time-Turner,” Hermione whispered, “and I got it from Professor McGonagall on our first day back. I’ve been using it all year to get to all my lessons. Professor McGonagall made me swear I wouldn’t tell anyone. She had to write all sorts of letters to the Ministry of Magic so I could have one. She had to tell them that I was a model student, and that I’d never, ever use it for anything except my studies. … I’ve been turning it back so I could do hours over again, that’s how I’ve been doing several lessons at once, see? But …
Harry Potter and the Prisoner of Azkaban, Chapter 21 - Hermione's Secret

It had to be kept a secret.

The more she uses it to do hours over again, the higher chance there is of somebody seeing something they shouldn't and starting to ask awkward questions. Or worse, two versions of Hermione running into each other. That's even harder to avoid if she's not conscious and able to react to situations that may arise.

She wasn't allowed to use it for anything except her studies.

You might argue that using it to sleep is kind of using it for her studies, since it would allow her to focus more and get more out of her classes. However, Hermione is very much about the letter of the law rather than the spirit, and likely would have rejected such a loophole.

  • 29
    Since a significant part of learning happens in your sleep, one could argue that a student's sleep is part of their studies. Aug 5, 2014 at 8:06
  • 5
    @CodesInChaos true, but I could easily see how an overachieving student like Hermione wouldn't consider that. Those types of students tend not to realize the importance of sleep.
    – David Z
    Aug 5, 2014 at 18:49
  • 6
    I think she'd soon run out of places to sleep with her avoiding old selves and all. Aug 5, 2014 at 20:54
  • 3
    Don't forget that Hermoine was also experiencing longer days. Say she had 6 hours of class time per day that she was doubling. That means the days she was experiencing were 30 hours long. If she only slept 8 hours a day, then she's spending ~3/4 of her time awake rather than 2/3.
    – Doresoom
    Aug 5, 2014 at 20:57
  • 3
    @CodesInChaos That sounds very much like a scientific fact that a twelve year old girl and the magical community aren't likely to be aware of. Aug 6, 2014 at 12:15

First, remember that classes are structured around those students who aren't bending time to their will, so they have to be taken during daylight hours. Hermione couldn't very well have crammed in some time-turner sleep and then taken night classes - these are essentially UK-College students, and the classes they take are during regular hours, likely running a bit late into the night since it's a campus-structure but still with regular lights-out time.

Second, remember that the time turner itself can't be used for more than five hours, according to Pottermore:

According to Professor Saul Croaker, who has spent his entire career in the Department of Mysteries studying time-magic:

'As our investigations currently stand, the longest period that may be relived without the possibility of serious harm to the traveller or to time itself is around five hours.'

While she could possibly get a nap out of it, any more would be seriously dangerous, and a mere nap when overlapping classroom time would not have helped matters much.

  • 10
    I can't believe this is the only answer to point out the five hour limitation - and perhaps three copies of herself (two in class and one in bed sleeping) is totally out of the question.
    – user11521
    Aug 4, 2014 at 23:07
  • 1
    I think any acceptable answer would need to include this caveat. It definitely sets some serious limitations on the use of a Time Turner. Aug 5, 2014 at 19:28
  • 6
    The five hour limitation is only there so no one gets the bright idea of killing Voldemort as a child.
    – kleineg
    Aug 6, 2014 at 12:13
  • 5
    @kleineg Or, contrawise, so that no Voldemort gets the bright idea of redoing the whole 'kill the Potters' shtick.
    – Zibbobz
    Aug 6, 2014 at 12:56
  • 1
    @Zibbobz ...That is a scary thought, or a good movie.
    – kleineg
    Aug 6, 2014 at 13:01

I've had another think about this and I've come up with another reason.

She physically couldn't. As we see in PoA when she turns time back there are two "copies" of herself. She and Harry see themselves doing the same things they did earlier that evening. Which means if she woke up in the morning and wanted a lie in when she spun back time she'd find herself in bed!

It's probably fair to assume that house elves/other students occasionally visit the dormitories during the day. To find her in bed all day every day would raise suspicion which rules out some complicated 24 hour sleeping thing.

In summary, why couldn't she use the time tuner to spend more time in bed? She was already in bed!

  • 2
    Well, there are other places she could have slept... Room of Requirement perhaps, or some other out of the way place.
    – user11521
    Aug 4, 2014 at 23:05
  • 2
    @Michael the RoR wasn't known about then Aug 5, 2014 at 7:44
  • 19
    Man, I can totally see this line of thought causing a "sleeping with herself" fanfic. Aug 5, 2014 at 10:41
  • 1
    I don't think any of these objections rule out using the time turner to get to bed a couple hours earlier than she otherwise would. Using it for that as well as classes would make her days even longer than the 26 hours they already were. Her classmates would see her come to the dorm for bed at a normal time, evne though she was also still somewhere else studying / doing homework (preferably private, to avoid discovery). Personally, I think I'd be happiest living on at least 25 hour days, probably be fine on 28 hour days. I always seem to stay up later and later. Aug 5, 2014 at 15:40
  • 3
    @GustavBertram The sheer number of paradoxes involved is scary enough as it is.
    – Pharap
    Aug 6, 2014 at 17:24

If she was ever caught she would have had it taken from her and she would have been unable to complete her studies. She was a very lawful student most of the time and did not want to be expelled.

From the Prisoner of Azkaban Chapter 21, Hermione’s Secret

Professor McGonagall made me swear I wouldn’t tell anyone. She had to write all sorts of letters to the Ministry of Magic so I could have one. She had to tell them that I was a model student, and that I’d never, ever use it for anything except my studies.

The stakes were high if she was caught using for trivial means. She probably wouldn't have wanted to betray Professor McGonagall's trust, as well. McGonagall vouched for her and would have possibly got into trouble if Hermione was caught acting out with it.

Prisoner of Azkaban Chapter 21 of Hermione's Secret, pg. 393

"Now pay attention", said Dumbledore, speaking very low, and very clearly. "Sirius is locked in Professor Flitwick's office on the seventh floor. Thirteenth window from the right of the West Tower. If all goes well, you will be able to save more than one innocent life tonight. But remember this, both of you: you must not be seen. Miss Granger, you know the law- you must know what is at stake.... you-must-not be-seen.

Also, these links.

Hermione Granger received one from Professor McGonagall in 1993, so that she could attend more classes in her third year than time would allow. Since McGonagall made her swear to not tell anyone about it, she did not mention it to Harry or Ron until the end of the school year, when she and Harry used it to travel back in time and save Sirius Black and Buckbeak from certain death. Special permission from the Ministry of Magic had to be sought to allow Hermione to use one, but her academic record ensured that permission was given.

Hermione put a lot of things toward her school and she did not want to be expelled. Remember this qoute.

Hermione: Now if you two don't mind, I'm going to bed before either of you come up with another clever idea to get us killed - or worse, expelled.

She probably would have broken the rule if she could justify it with a logical rationale, like if someone was about to die(Sirius Black or Buckbeak). Because when the need presented itself, Hermione didn't hesitate using it then. But she couldn't so she just worked harder cutting the "dumb" courses and cutting out play.


What you must understand, is that Hermione was the most dedicated student at Hogwarts. Sleep and other such wastes of time were immaterial to her. Also, if Professor McGonagall discovered that she had been 'misusing' the privilege of a time-turner which had been bestowed upon her, she "could be killed, or worse, expelled". Just kidding, I guess it was always a morality issue with her.

  • 6
    A thought does not simply evade Hermione's mind though.
    – Lancelot
    Aug 4, 2014 at 19:40

Because, in using time turner there was one rule in which user of time turner must not be seen by his/her old selves, if she had used it to sleep there was chance of getting seen by her old self,or other person who saw old self at different place at same time. That could cause a problem.


She isn't exhausted simply because she needs more sleep. She's exhausted because she's constantly jetlagged. Using the Time-Turner to go back 5 hours (say) is the equivalent of flying from the East Coast of the USA to the UK or Ireland. She must be doing this several times a week. Imagine hopping on a long-distance flight once every few days, flying around the whole world from west to east every week. Your body clock would be totally out of sync with the world around you. You'd be groggy during the day and unable to sleep at night, hungry at weird times but rarely during meals... it's no wonder she seems tired.

In all probability she does use the Time-Turner to catch up on sleep sometimes. I don't see that this would cause many more problems than being in more than one class at once.

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