In the first Harry Potter book, Molly is seen asking her children "what platform number is it again?"

Heart hammering, Harry pushed his trolley after them. They stopped and so did he, just near enough to hear what they were saying. 'Now, what's the platform number?' said the boys' mother. 'Nine and three-quarters!' piped a small girl, also red-headed, who was holding her hand. 'Mum, can't I go...' 'You're not old enough, Ginny, now be quiet. All right, Percy, you go first.' (Harry Potter and the Philosopher's Stone, Chapter Six, "The Journey from Platform Nine and Three-Quarters")

Why didn't she remember on her own? She would have been bringing kids there for the past 10 or so years, not to mention her own years at Hogwarts.

  • 94
    Maybe just for entertaining the kids? It is just like an old granny asks their grandchildren something easy so they can be happy?
    – arc_lupus
    Commented Sep 17, 2014 at 14:48
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    Perhaps there is more than one platform in the Wizarding World and their train schedule varies... Commented Sep 17, 2014 at 15:01
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    A number you use only once (or even twice) a year is easy to forget. I can never remember what voting district (18 or 19?) i am in, for example. Commented Sep 17, 2014 at 17:49
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    @RBarryYoung That's actually a fantastic point. Might be worth its own answer. We only remember the number because it's significant to the story, but when you're in the world all of that stuff is just day-to-day minutia. I don't remember my parents' zip code, or the last terminal number for Dallas at the airport, or anything at all like that. Hell, I forget what floor number some of my coworkers are on at the office. Comment is so spot-on that it's worth posting as an answer.
    – asteri
    Commented Sep 17, 2014 at 22:19
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    She asked on Parenting.SE "How do I get my daughter to remember the train platform she's using for the first time" and was told to try making it a game and "forgetting" the number.
    – user31178
    Commented Jul 22, 2015 at 1:13

7 Answers 7


The way it’s described in the books makes it sound like it was just a question for Ginny to answer:

“Now, what’s the platform number?” said the boys’ mother.

“Nine and three-quarters!” piped a small girl, also red-headed, who was holding her hand. “Mum, can’t I go…”

The boys go straight through the barrier, so they must be standing right next to it. It follows that Mrs. Weasley has led them to the right platform, so she does know what it is.

There’s no mention of her being flustered or frustrated (or at least, no more than you’d expect with Fred and George for sons) about being unable to find the platform.

ETA: I’ve seen several comments saying that perhaps this was a movie thing; it isn’t. This is what Molly says in the film, which Harry overhears after talking to the station staffer:

…same every year of course, packed with Muggles! Come on: Platform Nine and Three-Quarters this way.

She doesn’t seem particularly flustered or concerned, except to keep Ginny close by her side, and to make sure they all get through the barrier safely. There’s never any question about what the platform number is.

  • 4
    The most popular manipulative!Weasley plot point busted, 1+ coming your way. Commented Sep 17, 2014 at 19:36
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    Sounds like it is more of a movie-plot-inconsistency as I remember in the movie she did seem flustered/frustrated.
    – mikeazo
    Commented Sep 17, 2014 at 19:43
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    In the movie she was flustered/frustrated because she's trying to get 4 children ready to go away to school for an entire year, with another hanging on.
    – krillgar
    Commented Oct 21, 2014 at 12:11

This is probably for Ginny's benefit. Ginny will be starting at Hogwarts the next year, and Molly is asking a question to which she obviously knows the answer to, to see if Ginny can answer it.

She is basically quizzing Ginny, as parents often do. It would be absurd to think Molly doesn't actually know or remember the correct platform. With brooms, portkeys, Floo networks and Apparation, the Hogwarts train is probably the only train magic-born ever use.

And in the six years that Harry attended Hogwarts, the platform didn't change.

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    Just like asking the kids to "Remember where the car is parked!". Commented Sep 17, 2014 at 19:37
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    The Itchy lot?
    – krillgar
    Commented Oct 21, 2014 at 12:15
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    This answer is strengthened by the fact that they were already on the platforms 9 and 10. Commented Dec 26, 2019 at 12:19

There's a strong possibility that she's genuinely trying to work out which platform they're going to be using. In the Pottermore moment on Platform 9 3/4, JKR notes that there were other "fractional platforms" that wizarding trains use to transport witches and wizards to various magical destinations.

It's quite feasible that in other years, the Hogwarts Express set off from a different platforms and she's looking for confirmation which platform they'll be departing from this time;

"In choosing the number of the concealed platform that would take young witches and wizards to boarding school, I decided that it would have to be a number between those of the Muggle platforms – therefore, it was clearly a fraction. This raised the interesting question of how many other fractional platforms lay between the whole-numbered platforms at King’s Cross, and I concluded that were probably quite a few.

Although these are never mentioned in the book, I like to think that it is possible to take a version of the Orient Express off to wizard-only villages in continental Europe (try platform seven and a half), and that other platforms may be opened on an as-required-basis, for instance for large, one-off events such as Celestina Warbeck concerts (see your ticket for details)."

  • this was my thoughts as well, to me it would seem suspicious that 2 times a year a mass of weirdly dressed people some with owls would hang out in the same area on the train station, it seems much more plausible that the Hogwarts train could switch every couple years.
    – Himarm
    Commented Sep 17, 2014 at 18:22
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    @Himarm - If you think that's sufficiently weird as to attract muggle attention then clearly you've never been to a showing of the Rocky Horror Show.
    – Valorum
    Commented Sep 17, 2014 at 18:29
  • @Himarm Or just about any anime convention
    – Izkata
    Commented Sep 18, 2014 at 0:08
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    @Himarm In the Epilogue, taking place over 20 years later, they're still on 9 3/4. And i think in Snape's memory they're on 9 3/4 as well. That's a period of what, ~50 years?
    – Scimonster
    Commented Sep 18, 2014 at 14:31
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    Yeah, but strangely enough every time the book mentions it, it happens to be on the same platform.
    – ibid
    Commented Feb 26, 2016 at 16:13

What makes you think she didn't remember platform number? Parents (and other teaching figures) frequently ask questions whose answers they know, with the intended goal being for their children to provide the answer; it's a tool that helps the child remember facts.

It's like going to an amusement park and asking your kids "Okay kids, where did we park?" so your children remember where the car is if the family becomes separated.


The most likely answer is also the simplest (and least interesting). She probably forgot because she doesn't use it that often.

A number you use only once (or even twice) a year is easy to forget. I can never remember what local voting district (18 or 19?) I am in, for example. Who remembers their driver's license number?

OK, that's usually a long number, but what about your congressional district number? How about the street address of your school? These are all things that we tend to forget, not because they are hard to memorize, but simply because we don't use them that much, and on the annual or semi-annual occasion that we do, we can just look it up (or ask someone else), so it's not really worth trying very hard to remember long term.

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    Don't forget that the number is printed on their tickets, and she was in the correct spot before asking.
    – Scimonster
    Commented Sep 19, 2014 at 10:47
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    @Scimonster I take it you've never flown or anything. Pretty common to be like, "What the hell terminal am I going to?" and have to re-look at your ticket, even when you're right in front of it to double-check.
    – asteri
    Commented Sep 19, 2014 at 17:13
  • @asteri Nope, never had that while flying. :)
    – Scimonster
    Commented Sep 20, 2014 at 16:52
  • I have to say I've never had any problems remembering any long number - driving licence, credit card, I can reel them off as and when required. I'd do it right now to prove it but I like my identity where it is, thank you. Commented Sep 22, 2014 at 8:39

I read about a conspiracy theory: She said it deliberately to attract Harry to his family (Dumbledore warned her about Harry) but conspiracy theories don't deserve attention, although this specific theory is interesting.

In my opinion, this is a REAL question, it's possible that in his epoch, the platform had a different number.

  • Before you guys ask me ''But she take his sons to the platform a few years ago'' Could be Arthur Weasley who takes his children to the platform. Maybe her not works on the ministry yet.
    – NicolasTSH
    Commented Jul 22, 2015 at 0:14
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    This perhaps would be better as a comment than an answer. When you achieve sufficient rep you will be able to post comments on posts! In the meantime I suggest you go through our tour - you get a badge! Commented Jul 22, 2015 at 0:24
  • Agreed. Fan theories are fun but this isn't an answer to the question asked other than very tangentially
    – Valorum
    Commented Jul 22, 2015 at 7:24

The truth is J.K. Rowling made mistakes in the book and she admitted to that. No one would forget the number as commented above. Even if you use it one time, you also go to Diagon alley one time a year but they do not forget that. The fact she grew up in a wizard family and that was always the way, than would be common knowadge for the wizard world as much as the Minster or Hogwarts.

She purposely put that in there to go with the story or made a simple mistake like the misnumber of Horcrux's. (There was 7, Harry was 8 and the snake was 9 yet 7 were destroy)

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    Since you referred to Rowling admitting that she made mistakes while writing the Harry Potter books, it would be good if you edited your answer to include a direct quote of such an admission, to back that point up. Commented Feb 24, 2023 at 3:15
  • Even better would be a quote admitting a mistake about this platform reference, as there are a number of very plausible reasons for the question in the answers provided over the years.
    – FreeMan
    Commented Feb 24, 2023 at 17:19

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