Other contributors have said "How many words in a Harry Potter book?" is the same question as "How many words are in each 'Harry Potter' book?" If you believe that these are not asking the same thing and should be answered differently, click here
Philosopher's Stone- 76,944 words Chamber of Secrets - 85,141 words Prisoner of Azkaban - 107,253 words Goblet of Fire - 190,637 words Order of the Phoenix - 257,045 words Half-Blood Prince - 168,923 words Deathly Hallows - 204,796 words
Unless you count yourself you won't find out. You can however, find out the total word count for each book (see related questions). There are so many editions of the Harry Potter books and so many...
Last sentence of each book: First book: I'm going to have a lot of fun with Dudley this summer...."- HarrySecond book: And together they walked back together through the gateway to the Muggle...