How many witches and wizards are there in England? What is the magical population of the UK? This is a question that most folks who write fanfiction have pondered at least once. I seem to recall that somewhere JKR herself stated that there are roughly 3,000 magicals in the UK. Watching the movies, especially the final battle where thousands of Dark Lord supporters seem to attack Hogwarts, seems to contradict this image though, and we all know how bad Dear Jo is at mathematics. So I decided to waste a bit of time to see if I could come up with a reasonable SWAG at what the population would be.

Let's start off with some basic assumptions. We can speculate that there were 40 first year students when Harry started Hogwarts. I say speculate because it is always possible for there to be any number of students simply left unmentioned; JKR herself has stated that there are two other, unmentioned girls in the Griffindor class along with Hermione, Parvati and Lavender. But let's go with 40 kids. Assuming there are also 40 kids in each of the other six years there is a total of 280 students in Hogwarts during Harry's tenure. Now to extrapolate this out to the size of the population: if we assume that all magical children attend Hogwarts we conclude that there are 280 people in the British magical population between 11 and 18.

Now, if we look at the population as a whole and try to get a handle on the age spread of that we can draw some conclusions. We know that magical live longer than non-magicals, but how much longer? We know that Dumbledore is approximately 125 during the HP series, and we know that at least one member of the Wizarding Exam Board was an examiner when Dumbledore took his OWLS so we can assume that she is around 165 and still working. So let us assume that magical live twice as long, on average, as non-magicals; that would make Dumbledore roughly the equivalent of a school principal in his early 60's, which seems reasonable, and dear old Grizelda Marchbanks in her 80's and still working. From personal experience I have worked with a couple of folks who worked well into their 80's so this is also reasonable. It is also easy to work with.

So now we look at the population vs. age distribution of Great Britain and simply double the ages. Not incredibly accurate but reasonable for a SWAG. A little work tells us that if magical Britain follows the same age distribution as Non-magical then 5.5% of the magical population should be between the ages of 11 and 18. If all school age children attend Hogwarts and there are 280 students then the total magical population of Great Britain is approximately 5100; which is remarkable not too far off from what JKR posited. In the 1190's the total population of Great Britain was roughly 58 million so the idea that magic occurs in about 1 in 1000 is pretty close to the mark. This conclusion also fits well with the facts that there is only one totally magical village in Britain, namely Hogsmeade, and one major magical shopping district, Diagon Alley, likely with a permanent magical population similar to Hogsmeade. The village of Godrics Hollow has a significant magical population, with at least the Potters, the Dumbledores, and the Bagshots living there, and several other clusters of families, such as the Weasleys, Lovegoods, and Diggorys in Ottery St. Catchpole, scattered throughout.

Now in the US in the 1990's the population was approximately 250 million, or roughly 5 times the size of GB. So we can then extrapolate that there would be roughly 25000 magicals in the US and reasonable up to 5 schools of magic, if we keep the size of each to around Hogwarts standards. We are told of only one in canon, the Salem Witch's Institute, assumedly located near Salem Massachusetts. So where would the others be located? The first five colleges founded in the US were: Harvard in Mass, William and Mary in Virginia, Yale in Connecticut, Princeton in New Jersey, and U Penn in Philadelphia. If SWI is in Mass, it may be safe to assume that one would be located in Virginia and at least one in the mid-atlantic region of NJ/Penn.

One of my personal favorite fanfic writers, DrT, wrote several stories where the Druids left England in a manner similar to how the Puritans did but traveled further west before settling, establishing schools in the American far west. Excellent reads if you are interested and his work is posted on several sites, including , Ficwad, and Schnoogle. He is a prolific writer with a wide range of plots.

Anyways, to conclude my little piece of distraction, we can reasonably guess that approximately one in a thousand births result in a magical child. There are roughly five thousand plus witches and wizards living in Great Britain and twenty five thousand in the US. If there is only one magical school in Great Britain there are likely five in the US and considering the greater geographical size of the US these are likely boarding schools as well. Maybe next time I have an hour to kill I'll look at the Galleons to dollars conversion and see how much sense the 1G to $5 rule of thumb goes?