In the linked question (How does the Hogwarts Headmaster know whom to invite to school?) it is mentioned that the Ministry doesn't keep track of which children are capable of magic. If this is the case then how does The Trace get applied to magical children? I seem to recall that the trace is only active for Hogwarts students but this could be wrong. If that is the case does the trace even apply for students that are magic but don't go to Hogwarts?

To make it more clear - If the Ministry of Magic doesn't keep track of which children are capable of magic then how can they apply the trace to wizards of a certain age? If it happens automatically then anytime they use magic there would be a record and thus the Ministry would know which children are capable of magic.

5 Answers 5


The books never mention how the Trace is applied to young witches and wizards, and Accio Quote doesn't turn up anything relevant from interviews with Rowling. Any answer would have to be speculation. So I'll speculate.

I see two parts to this: how the Trace is applied, and when. Let's start with how.

Nobody who talks about the Trace in the books -- neither Moody, nor Ron or Hermione -- ever actually explains how or when it's applied, but we can gather some hints. From Ch9 of DH:

[Hermione:] "What if the Death Eaters have found a way to put [the Trace] on a seventeen-year-old?"

[Ron:] "But Harry hasn't been near a Death Eater in the last twenty-four hours. Who's supposed to have put a Trace back on him?"

So Ron is suggesting that a witch or wizard must be in the presence of the person they're applying the Trace to. It's not some country-wide enchantment that automatically applies the Trace to every wizarding child at birth / age eleven / first time they use magic / whatever; it's something that is done deliberately and in person.

It's possible that Ron doesn't actually know that the Trace must be applied in person, and is just guessing at the nature of the magic. But Ron's dad works at the Ministry, so it's entirely likely that he knows more about magical bureaucracy than Harry does; and Hermione doesn't correct (or even challenge) his assumptions. So that's fairly authoritative.

Now, as for when the Trace is cast on a person. It's obviously in effect by the time the student goes home after their first year at wizarding school, but it could start any time before that, perhaps even as early as birth. Can we narrow that down?

It's clear from numerous places in the books that the Trace isn't considered relevant until the student begins attending wizarding school. For example, in chapter 33 of DH:

[Snape:] "...and the Ministry can punish you if you do magic outside school, you get letters."

[Lily:] "But I have done magic outside school!"

"We're all right. We haven't got wands yet. [...] But once you're eleven [...] and they start training you, then you've got to go careful."

And in Ch13 of HBP:

[Dumbledore:] "But you should know that Hogwarts can expel students, and the Ministry of Magic -- yes, there is a Ministry -- will punish lawbreakers still more severely. All new wizards must accept that, in entering our world, they abide by our laws."

However, there's no indication of whether or not the Trace is actually in effect before the student enters school. Perhaps the Ministry simply ignores the Trace until the year the child would start attending wizarding school.

I can think of four main points of contact when the Trace could be applied.

  1. At birth. If the child is born to at least one wizarding parent (e.g. Ron, Harry), it could be that registering your newborn with the Ministry, and having the Trace applied, is just part of the paperwork, like Muggle parents filing for a birth certificate (and with similar bureaucratic or legal consequences if the parents fail to do so).

    However, it's less clear how this would work with Muggle-borns. Muggle parents don't meet a representative from the wizarding world until their child is soon to start their first year at wizarding school. Even if the child's name was down since they were born (as Hagrid said Harry's was), the new parents don't know that yet; they would have no way to know they needed to go to the nearest Ministry of Magic office to fill out paperwork, and have spells cast on their child.

    It's possible that the Ministry has undercover workers in Muggle hospitals, just like they do in the Muggle government, post office, etc., and those undercover workers surreptitiously apply the Trace without informing the parents. But not all children are born in hospitals, and there are a lot of hospitals and not that many Wizarding folk to staff them all. So while it's possible, it seems awfully unlikely.

  2. First contact. Harry was assumed to already know about magic, so his first contact from Hogwarts was simply the usual letter. Muggle parents, however, are visited in person by a member of the Hogwarts staff prior to their child's first year at Hogwarts (and this is the first time the parents are told that they aren't going crazy, and their child is actually a witch or wizard). It's possible that that staff member could apply the Trace as part of the visit.

    Is there anything in the books to back this up? Harry's experience obviously isn't relevant; he just gets a letter (until his letters fail to get delivered, anyway). Hermione's visit is mentioned after the fact, and not shown in the narrative. But we do see Dumbledore's visit to Riddle. If he applied the Trace then, it's not mentioned.

    Again, it's possible that the Trace is applied surreptitiously. But the only time Dumbledore takes out his wand during this encounter is to demonstrate magic (on the wardrobe, and then on its contents); he never turns his wand on Riddle directly. It's hard to imagine applying an enchantment that lasts six years without using a wand. (Okay, Harry's mother did better than that without a wand; and besides, it's Dumbledore. But still.)

  3. When the student buys their wand. Given Snape's quote above, especially the bit about "we haven't got wands yet", this seems like a very practical time to apply the Trace. There are very few wandmakers, so it's entirely possible that they have to follow strict Ministry regulations.

    There's no mention of Ollivander casting a spell on Harry. But it's possible that an enchantment is placed on the wands ahead of time, so that as soon as the wand chooses the wizard and establishes a bond, the Trace kicks in as well. (However, this conflicts with Ron's information that the Trace is cast in person.)

  4. When the student starts their first year at Hogwarts. If students had to register for classes when they arrive, the Trace could be applied then -- but they don't; the classes are assigned. The only special things first-years do are:

    • Cross the lake in the boats (but there's nobody who could cast the Trace on them then; the only adult with them is Hagrid, who isn't allowed to do magic);
    • Gather in the side room prior to the Sorting ceremony (but there's nothing to suggest any special enchantment is applied while they're there); and
    • Try on the Sorting Hat. Perhaps the Hat casts the Trace as they try it on. It's not clear that the Hat can cast spells of its own (beyond the obvious Legilimency), but it is a Thinking Cap, so who knows?

It's difficult to find an answer that fits all the facts. The Trace must be cast in person, but the narrative never reports anyone casting the Trace on Harry. It could happen at birth, but then special arrangements would have to be made (either at time of birth or sometime later) for Muggle-borns, and we never see those arrangements being made; they certainly don't happen on the day the students first arrive at Hogwarts, because the Muggle-borns never leave the group.

I personally like the idea of the Trace taking effect as the student buys their wand, as it would also cover students who are home-schooled or go to other schools (as long as there's not a black market in Trace-less wands), but it conflicts with what (little) we know about how the Trace is cast, so that's a mark against that theory.

The only answers that seem to fit everything we know are:

  • McGonagall casts the Trace on the first-years while they're in the side chamber waiting to be Sorted -- but without getting out her wand, and without them noticing; or
  • the Sorting Hat casts the Trace as it Sorts them.

Of course, there's always one final possibility: Rowling retconned the Trace into book seven for plot reasons, and it doesn't actually fit with anything that came before. Honestly, I think that's the most likely explanation of all.

But if we're sticking with canon, I'm probably going to go with the Sorting Hat.

  • Regarding #2, I just don't think Hagrid could have applied the trace without Harry at least noticing something strange (and then it should be in the book), if he could cast it at all.
    – Kevin
    Feb 12, 2012 at 3:46
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    Sure, but if Harry had gotten his letter, Hagrid wouldn't have been sent at all. Children born to Wizarding parents normally don't get a "first contact", so even if that's when the Trace is cast on Muggle-borns, there has to be something else for wizard-borns like Harry.
    – Joe White
    Feb 12, 2012 at 4:01
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    @JoeWhite If it was retconned in, then what about Harry being accused of Dobby's magic in Book 2?
    – Izkata
    Feb 14, 2012 at 0:51
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    @Izkata, I should have been a little clearer about that: I think the idea of a specific mechanism with specific rules was retconned in. The idea was there before, but not explained in any level of detail -- it was just magic, so the rules didn't have to be consistent.
    – Joe White
    Feb 14, 2012 at 12:49
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    When the wand is given -> what about second-hand wands ? At least Ron and Neville started their first year with an inherited wand. But they are not muggleborns, one can imagine that the trace is indeed applied when buying the wand, and if your child uses a second-hand wand you have to go to the ministry to get the trace.
    – Petit Lama
    Oct 25, 2015 at 11:00

You're making the assumption that just because the Trace can be cast by a person, it has to be cast by a person.

And given that the Trace breaks at 17 i.e. when a wizard/witch comes of age, it sounds more like the three are clutching at straws when they talk about applying the trace to a 17 year old, and 'if the death eaters can do that, who knows how they applied it' sort of thing.

Taking on what we know about Hogwarts letters, there is a magical quill which detects and records the birth of every magical child. The Ministry however does NOT have access to this list. So it follows that they are not able to go out and perform the trace on every magical power, more, they would likely lack the manpower.

Looking at how the Trace works, it seems that it picks up any and all magic cast in the presence of an underage witch/wizard (and if there's a muggle around, but says nothing about magical creatures like house-elves and dementors) but not who casts it. This again implies it is not cast on the person themselves. This combined with that it breaks when they come of age suggests the Trace is more fundamental in nature.

My theory? The trace is a nation-wide (possibly global, but we lack information about that) enchantment laid down by a Ministry of Magic of Old, possibly Merlin (seems his style) as a protection on children, particularly those born to muggles who would face fear and prosecution due to their powers. This allowed the ministry (or whatever magical government existed at the time) to locate and protect children who may be in danger from muggles. This has deteriorated in our time into a method of keeping track of wizarding offspring and keeping them in line. It detects what spell is cast, where it is cast and whether or not a muggle is present. Also, the locating is extremely accurate (at least to a household, as the ministry knew the hover charm was cast in 4 privet drive in book 2) I would think that there's an object, maybe some sort of map, in the Department of Magical Law Enforcement which detects and displays all this information.

Hope this helped!

  • 1
    I believe your explanation must be correct. Ron's statement is indeed the only one that contradict this, and I to am happy to dismiss it because he likely doesn't know how the Trace works. In fact, a nation-wide enchantment that records all magic done around underage children would also be a great way to power the magical quill in Hogwarts. Any underage wizard is likely to perform some accidental magic during their childhood. We know about the few instances Harry has did this. The quill just has to identify these accidental magic, and there's your list of young wizards and witches.
    – b_jonas
    Mar 23, 2013 at 20:14
  • Wasn't Merlin long dead by 1689 when the International Statute of Secrecy was enacted? The Trace wouldn't have been needed or applied before then… May 19, 2015 at 9:34

I remember a passage where they mentioned that the Ministry can't tell specifically who used magic in a house, just that it was used. So the trace isn't on a specific person per se but at a specific location or area. For example, the Ministry knew that it was Harry who fired off the Patronus when he and Dudley were being attacked because he was the only magic user in the vicinity.

  • 1
    You're right...Dobby did intentionally frame Harry by using magic too. But I remember that Ron mentioned (can't remember exactly when) that the ministry can't tell who was using magic in a house full of wizards they had to rely on the parents to enforce the rule. I think it was when Ron had used magic and Harry asked him about the trace. Feb 6, 2012 at 3:31
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    I don't think it's on a fixed place like you're suggesting -- it's more like an area centering around the person (so it moves when they do). In OotP, Harry wasn't near the Dursleys' house when he cast the Patronus, yet the Ministry was well aware that he used magic in the presence of a Muggle.
    – Joe White
    Feb 7, 2012 at 4:19
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    According to OotP Ch1, the dementors showed up when they were in the alleyway where Harry had first seen Sirius, which PoA Ch3 says was "several streets away" from the Dursleys'. You think the Trace has a half-mile radius or more? Harry didn't get a letter when Mundungus Apparated away in OotP -- the Trace's range doesn't even extend across the street.
    – Joe White
    Feb 11, 2012 at 23:53
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    @JoeWhite I agree with the first part of your comment (they were too far for a localized trace), but I'm not so sure about apparition triggering the trace - otherwise the Ministry could tell where Harry had gone with Dumbledore in book six.
    – Kevin
    Feb 12, 2012 at 0:54
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    @JoeWhite - didn't Moody use a disillusionment charm? Wouldn't they have caught that?
    – chama
    May 22, 2012 at 14:09

Just to add to the already complete answers, as specified in this answer, the children have to accept entering the world of magic. This probably creates a magical bounding to the magical laws as edited by the Ministry of Magic.

It is only speculation on my part, but I would think that the acceptance of those laws imply that the trace is magically set on the children as part of the "contract".

That speculation would not actually contradict Ron's observation: without the contract acceptance, the only way to place a Trace on someone is to actually be in presence of the intended target.


Could it be the trace the wandmakers put on the wand traces their magic to know when it's used and the trace in person spell is for location not whether or not the person is using their wand?

  • Do you have any evidence to support this theory?
    – Rand al'Thor
    Dec 19, 2018 at 4:27
  • I did not quote anything therefore i dont have anything to quote as i did state “idk im high” 🤷🏿‍♀️ Just assuming though
    – Zoey
    Dec 19, 2018 at 5:03

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