I made this thread to clear up confusion, as I had a reply to my article about something related to it. I gathered a lot of information before writing this.
Since this thread addresses a rather small issue, I could expand it to include many other topics about Wizarding Britain?
Anyway:
Overall population of Wizarding Britain:
The population of Wizarding Britain (and Ireland) seems to be around 12,000. We come to this figure by the few instances that Rowling points out about population in the Wizarding World.
1. Harry estimated that 200 Slytherin supporters arrived at a quidditch match. This means that there are around 800 students in total at Hogwarts.
This is a strange number, considering there were only about 40 students in Harry's year. (~10 per house) However, Harry's year could have an especially low number, due to a very low birthrate during the First Wizarding War.
2. By the demographics of muggle Britain, children aged 11-18 make about 10% of the population. Since wizards and witches live for much longer, the percentage of students would be even lower. If we take it at 6%, the total population becomes 12,000.
This makes sense. Harry observes hundreds of wizards in the Ministry atrium, and also is told that 500 ministry workers built the quidditch stadium.
3. Great Britain has about 1% of the world population. Assuming that it also has 1% of wizarding population, the population of the Wizarding World is around one million.
Again, this makes sense. The Quidditch World Cup stadium could hold 100,000.
Purebloods
A pureblood is a wizard or witch who have a purely of approximately pure magical heritage. This means there are no muggles in their close family trees, though this very rarely is ever the case. Another description is that a wizard or witch is pureblood if all four of his or her grandparents were wizards and witches.
If we take the former description, only a few families are still extant, and due to inbreeding, the number of true purebloods is always either stagnant decreasing. Currently true purebloods represent about 3% of the population.
If we take the latter description, purebloods are not all that uncommon. By general count of Harry's year-mates, about 25% of Wizarding Britain is pureblood.
Half-Blood
A half-blood is either a wizard or a witch with known magical heritage, or a wizard or a witch who's grandparents were both magical and non-magical.
Either way, half-bloods number far more than either muggleborns or purebloods. This number would go from 70% to 95%, depending on the definition.
Since Magical genes are dominant, squibs are very, very rare.
Muggleborns
Muggleborns are wizards or witches who have no magical heritage whatsoever. They are quite rare. Apparently, Harry's year had just two (Hermione and Justin.) If we take this number and apply it to the Wizarding Britain in general, about 2% of Wizarding Britain is muggleborn.
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Summary:
Population of the Wizarding World: Over a million
Population of Wizarding Britain (and Ireland): ~12,000
Pure-bloods in Britain: 300-3,000 (3%-25%)
Half-bloods in Britain: 8,500-11,500 (70%-95%)
Muggleborns in Britain: 350 (3%)
Squibs in Britain: ~100
Overall Ratio of Wizards to Muggles: 1 : 5600 (Or <0.02%)
Last edited by Franklin O'Neil on Tue Jan 29, 2013 8:33 am; edited 1 time in total