How many students at Hogwarts?

[hp_lexicon]

No: HPFGUIDX 46412

There are actually about three hundred, it would seem, although 
there is plenty of debate on the subject. Here's the evidence from 
the books themselves: 
There are more or less ten students (depending on the vagarities of 
the Sorting) in each house per year, five boys and five girls. 
There are twenty broomsticks lying on the ground awaiting the first 
year Gryffindors and Slytherins for their first flying lesson, which 
bears that number out. 
A double class of potions--Gryffindor and Slytherin--has twenty 
cauldrons set up. 
For a double class of herbology--Gryffindor and Hufflepuff--
Professor Sprout has twenty pairs of earmuffs ready. 
Harry's class in Gryffindor has the following students in it: 
Harry Potter 
Ron Weasley 
Seamus Finnigan 
Dean Thomas 
Neville Longbottom 
Hermione Granger 
Lavender Brown 
Parvati Patil 
two unidentified girls 
If there are more Gryffindors of that year, isn't it strange that we 
haven't heard about them in four years' worth of books? Not a one 
has spoken up in class, has been part of any parties or activities 
in the common room, or anything like that. Judging by the numbers 
cited above for herbology, flying, and potions, they must not even 
be in the same classes. If there are any others, where in the world 
are they? We do have evidence of two more girls, but they have been 
awfully quiet. 
Assuming the ten students per house per year numbers, that would 
work out to forty students per year for a total of about 280 
students. This meshes with the several times that Harry 
sees "hundreds" of people in the Great Hall (in SS when Harry is 
Sorted and GF when he's chosen for the tournament, for example). 
The number of teachers would also suggest a fairly small number of 
students. In GF Harry looks along the staff table in the Great Hall. 
He notes teachers by name until he gets to Dumbledore in the middle 
of the table. He has named Flitwick, Sprout, Sinistra, Snape, and an 
open chair for McGonagall on that side, which means that there would 
be the same number on the other side, for a total of eleven, 
counting Dumbledore. Add Trelawney, who we know doesn't attend these 
functions, and we get an even dozen teachers. Twelve teachers would 
not be able to teach classes to a thousand students, unless they 
used Time Turners constantly, which doesn't seem likely. 
The sorting at the beginning of PA takes only as long as a fairly 
quick conversation between Harry, McGonagall, and Madam Pomfrey and 
a subsequent chat between Hermione and McGonagall. The time of these 
chats seems quite short. But if there are a thousand students at 
Hogwarts, there would be between 150 and 200 students to sort every 
year. Even at the rate of two per minute, that would mean the 
sorting would last for over an hour. Would the rest of the students 
really be willing to sit for that long waiting to eat? I think it 
would get a bit long. And the sorting we've witnessed in the books 
certainly doesn't seem to last over an hour. 
On the other hand, there are about a hundred carriages to take 
students to the castle from the train station in Hogsmeade. There 
are also 1200 seats available around the tables at the Yule Ball. 
And during one Quidditich match, there are two hundred Slytherin 
supports in the stadium when we know that Ravenclaws and Hufflepuffs 
were backing Gryffindor. So there are some references that support 
the "thousand student" concept. But by far most of the evidence 
suggests a much smaller number... 


Source: The Harry Potter Lexicon
http://www.i2k.com/~svderark/lexicon/hogwarts_howmany.html

Steve