"Now I'm not only a Mormon cliché; I'm also a puppy." - Claudio
Question #89723 posted on 05/28/2017 2:26 a.m.

Dear 100 Hour Board,

I don't want to scare you, but I'd like to talk about horcruxes. I've got a few questions. First, how many can you really make, I've heard it's 7, well I guess 6, but is there anything really stopping me from going higher? Second, how exactly would my soul be divided? I mean, does it divide in half the first time I make one?
Because if it keeps dividing in half, and leaving the remaining half soul in a horcrux, then by the time I split my soul into its seventh part, I would only have 1/64th of a soul left in my body, while my first horcrux would have an entire half soul, that doesn't seem fair, does it?

-Tom Riddle


Dear Tom,

Tell me about it.

-Lord Voldemort


Dear Tom,

You got nothing on the Voldemort from Harry Potter and the Methods of Rationality. Now that's a scary villain!

He snuck a Horcrux onto the Pioneer 11 spacecraft, which is currently lost in deep space somewhere. Immortality achieved.



Dear terrible person,

Here is a formula to help you figure out how much soul you will have left after making any given number of horcruxes:

[remaining amount of non-horcrux-embodied soul]=1/(2[number of horcruxes])

Or, if you prefer, I have included a table for your perusal:


Fraction of Remaining Soul



































































...and so on. You may find this table useful to you. For example, it seems like it would be really risky to walk around with approximately one eight billionth of a soul, so thirty-three horcruxes is almost certainly too many. 

Hope this helps.



Dear Riddle,

As Sheebs demonstrated in her table, the fraction of your soul you get to keep gets exponentially smaller with every division. As she pointed out, with M being the number of horcruxes (or divisions) you make, you get to keep 1/2M of a soul. (Again refer to Sheebs' table to see this relationship.) Now the limit of this expression as M approaches infinity is 0. However, the funny thing about limits is that you don't have to actually arrive, and in the case of 1/2M, you don't. So if we just go off of the criteria that you need some soul in you to survive (no matter how infinitesimally small that soul is), and assume that the soul isn't composed of physical matter (per Ento's point below me) then you can technically continue making horcruxes ad infinitum.

But we don't live in a world with infinitely many people in it, so your next limiting factor is the number of people. Currently it's 7.3 billion. (Plugging that into our handy-dandy equation gives us that you would have approximately 4.4971x10-2197518969 of a soul left, but hey, that's still some soul!)

The next thing to consider is how much time it will take to kill all those people. I mean, technically your horcruxes grant you immortality, but my guess is that when you go on your killing spree, the survivors will be highly incentivized to stop you, so living forever isn't necessarily a given. So, because I can, I'm now going to go into approximately how long it would take for you to kill everyone in the world while making a horcrux with every killing.

Right off the bat, we can see this will take a bit longer than just Avada-Kedavra-ing everyone. "But wait," some reader says "didn't Voldemort manage to turn Harry into a horcrux without some extra spell?" Eh, Harry wasn't truly a Horcrux. Buried in the depths of this article is a quote by J.K. Rowling backing me up. Essentially, Harry wasn't cursed/evil like the other horcruxes because Voldemort didn't go through the proper process, though he was close to being a horcrux.

The books never specify the exact requisite spell for making a horcrux, but I think it's safe to say it's complicated. Let's assume this spell costs you 3.5 minutes of time (cause you get horrifically efficient at it). Actually killing people will go pretty quickly. Using the highly accurate and scientific method of muttering "avada kedavra" under my breath repeatedly (12 times to be exact) while in the library, and waving my finger like it's a wand, I came up with an average killing time of .671 seconds. You might get faster with experience, but my guess is that you won't be focusing on constantly speaking as fast as you possibly can, so I'm just going to say this value is constant over time. Another thing to add onto your murder time is resistance, and taking the time laugh in a high-pitched, evil manner (you know, adding that special personal touch). Note that I'm assuming you're taking the craftsman's approach here, and killing people individually. You probably don't need to laugh every time you murder (we don't want to go overboard here), so I'm going to suppose that you laugh for 1 out of every 5 killings, where each laugh has an average duration of 3 seconds. With an even distribution, let's factor in 5 seconds per person for resistance.

Without yet adding in travel/sleep/reveling in your evilness time, we have a rough total of 50,063 years for time needed to make a horcrux per every currently living person.

But if it's going to take you 50 thousand years to kill us all, how long before you actually get around to the general Board readership (i.e. the US)? Well, let's start looking at in your between murdering times, like traveling to your next victims.

Dividing the world into Europe, Asia, Africa, North America, South America, Oceania, and Antarctica, we conveniently have the population densities for each region here (which will be useful later on*). Let's say you commence your horcrux spree in Europe, successively moving on to Africa, South America, North America, Asia, Oceania, and finally Anarctica. Thanks to the ability to apparate, you can travel much faster than the average muggle, helping to cut back significantly in this department. However, apparating has its limits, so no big intercontinental apparition is allowed. Luckily for you, the shortest distance between Europe and Africa is only about 14 km, so is still within the range of apparating. Unfortunately for you, some other continents aren't so close, so you'll have to resort to brooms. 

I'm sure you'll have the best broom looting the now-empty shops can turn up, so you'll probably be able to fly at about 241 km an hour. As Africa and South America are 2575 km apart, that trip will take you 10.7 hours. North and South America are only separated by the isthmus of Panama, so again that will be within apparating bounds. If you leave from Alaska to Russia, there's only a distance of ~88 km (55 mi) and so you'll probably be able to apparate (though I'm not sure if a less adept wizard could). Asia and Oceania are separated by 7560 km, so that will cost 31.4 hours. Finally, the journey to Antarctica (to kill off those scientists) is 6,685 km, or 27.7 hours. 

For simplicity's sake, let's say you can kill everyone within a 10 meter radius before having to apparate to your next location, and that each apparition eats up 5 seconds. The following are your continent kill-times (using landmasses from here):

Europe: 5111.87 years (you have 1.265X10-2236954 of a soul left).

Africa: 8386.88 years (Alas, I was going to keep a running soul total, but Wolfram Alpha isn't working, and my graphing calculator ran out of batteries quite some time ago, so you all are just going to have to imagine the ever diminishing numbers to the side. Or, you know, plug the numbers into the formula yourself, but who would ever go to that trouble? That'd be crazy...)

South America: 2925.72 years (even less soul than before).

North America: 4009.19 years (imagine a super small number; the amount of soul you still have left is probably smaller).

Asia: 30492.36 years (repeat the imagining process, but now go even littler).

Oceania: 278.41 years (I mean, at this point probably even Dementors can't sense your poor, fragmented soul).

Antarctica: 20.97 years (hah, you can just refer to the above paragraphs to know how much soul there is left in your now very old and wizened body!).

This comes to a total of about 51,142 years, with 16,424 years before you arrive to North America. So, all you readers, just pass down this answer through the generations. Your 821st great grandchildren may be in trouble. 

Alternatively, opposed to killing the world population, I guess you could leave enough survivors in any one place who can continue having kids that could then be turned into horcruxes (again with enough survivors to produce a new generation). I think this might finally be getting into realm of that which is too morbid even for me, though.

~Anathema, who probably derived far too much morbid glee out of writing this answer

*Guess it didn't turn out to be important, but maybe you can do other cool things with that information


Dear Tom,

While I appreciate the rigor with which Anathema is treating the question of how many horcruxes one could make (and how quickly), I think she's making a couple of assumptions about horcruxes that are not supported by any of Rowling's writings.

First of all, if the soul is material, then it can only be divided into so many pieces. 27.13 billion (the 2013 estimate of the world population, which is what Wolfram Alpha gave me) pieces is way too many. That's more than 102,000,000,000 pieces, and the entire universe has "only" 1078 - 1082 atoms in it. The idea of a finite number of possible horcruxes is further supported by Dumbledore's observation that Voldemort's soul had been split so many times that it had become unstable, and that was after just five horcruxes. But I'll go more into unstable souls and how I think they split after covering a couple more assumptions.

Second, the books never say that making a horcrux splits your soul in half. All they say is that murder splits your soul, and that a special ceremony (which was apparently too horrific to include in the main books, but my money's on some form of cannibalism) can complete that separation and store a fragment of your soul inside another object.

Third, let's not forget the First Fundamental Law of Magic, which states, "Tamper with the deepest mysteries — the source of life, the essence of self — only if prepared for consequences of the most extreme and dangerous kind." These consequences are never detailed, but Dumbledore's discussion of "The Warlock's Hairy Heart" (found in The Tales of Beedle the Bard) explains how, "in seeking to become super-human this foolhardy young man renders himself inhuman." By extension, it could be postulated that, by altering the soul in the pursuit of eternal life, one renders oneself incapable of truly living. Even if there were no other physical or metaphysical limitations to the number of horcruxes that could be made from one soul, one should carefully consider how far they are willing to go in their pursuit of immortality.

Now, to wrap things up, let's look at an analogy for soul-splitting as I think of it. Let's think of the soul as a piece of glass. When you murder someone, you make a cut into that piece of glass, and then when you do whatever it is that you need to do to make a horcrux, that wedges that cut to the side so that it breaks. You can't control how it breaks, or how big the piece is, you just take the smaller of the two pieces and stuff it in something else. Eventually, your piece of glass is so small that you can't cut into it again without it spontaneously shattering. When that happens is probably random, and will depend on how each successive break goes, along with how many times you cut into it without actually breaking off a piece, but I would advise not going too crazy with it.

-The Entomophagist


Dear Tom,

I appreciate the time Anathema spent calculating all that, but I think there are a few points she overlooks. By the time Voldemort tried to kill Harry, his soul was already so mutilated that it split unintentionally. As Dumbledore put it so eloquently, "He had rendered his soul so unstable that it broke apart when he committed those acts of unspeakable evil, the murder of your parents, the attempted killing of a child."

To me, this implies that all murder is so evil that it has the potential to split your soul, even without whatever process goes into making a Horcrux (Okay, maybe not EVERY murder, since Voldemort murdered plenty more people after his return in Goblet of Fire. But I think killing people just for the sake of making as many Horcruxes as possible would probably qualify as "unspeakable evil"). So once your soul is split into enough pieces, it will be so unstable that it will split every time you commit some "unspeakable evil," even if you aren't intending to split it. In theory, that might just save time off Anathema's 3.5 minute estimate, allowing you to kill everyone even faster and make Horcruxes to your heart's content.

But remember that in the case of the Potters, the piece of Voldemort's soul immediately attached itself to the nearest living person, namely Harry. So theoretically, every time Voldemort (or whoever is making these theoretical Horcruxes) kills someone, his soul will be so unstable that it will split and a piece will attach itself to the nearest living person, which would greatly complicate the idea of killing everyone. You'd probably want to let the people who share a piece of your soul live, but it would be a whole complicated process to figure out who already had a piece of your soul, especially once you can't feel it if you split your soul, nor can you tell if a piece of soul is destroyed. Killing people in a logical order would be entirely ineffective, because you'd be killing parts of your soul right along with the nearest geographical people, therefore you'd never make any progress.

If you want to make Horcruxes just for the sake of having lots of Horcruxes (even if they aren't true Horcruxes), then maybe the logistics of it won't bother you so much, but being methodical could actually be your enemy--it would be better to kill randomly so you don't negate any of your work by accidentally killing people who already wield a portion of your soul. However, if you're making Horcruxes for the sake of actual immortality, and you're wanting to follow the actual process for doing so, then some caution is probably required so your soul doesn't reach the point of splitting unintentionally, because after that you won't have any control over the situation.

It's possible that the point at which your soul becomes unstable would differ for every person, but I think once you only have something like 1/128th of a soul left, any goodness left in it won't be enough to make a difference. So assuming Voldemort is a reasonable example, you can only make six true Horcruxes. After that, your soul would be so unstable that you would never have any control over the splitting, therefore you would never be able to make a true Horcrux again (unless, in theory, your soul could split twice over the same murder, once unintentionally and once via the actual process of making a Horcrux. But that's getting way too complicated, and we here at the Board always try to avoid complicated hypothetical answers).