credit - Mugglenet
NOTE: Many of these book mistakes were corrected in later versions, so the mistake may not appear in your HP book.

Book 1 Mistakes

* In Book 1, on page 27 (American paperback), it mentions that the snake in the zoo winked at Harry. Harry can't be blamed for being so surprised, as snakes don't have movable eyelids.

* When Hagrid comes and gets Harry out of the little hut on the rock, they use the boat that the Dursleys used to get to the rock. So how do the Dursleys get off the rock?

* On Harry's equipment list in the letter from Hogwarts, "1 wand" is listed twice. This was corrected quickly and only appears in the earlier versions.
* Harry's letter from Hogwarts says he may bring a cat, an owl, or a toad, but Ron brings his rat, Scabbers.

* Arguable: When Hagrid brought Harry to Diagon Alley for the first time, Harry heard a woman say "Seventeen sickles an ounce for Dragon Liver. They're mad." But Hagrid told Harry that there were seventeen sickles in a galleon. So that would be like saying "100 pennies" instead of a dollar. Think of it this way: if the Dragon Liver weighed three pounds, a galleon (or for our purposes, a dollar) per ounce is quite a lot of money.

* Harry buys the book One Thousand Magical Herbs and Fungi, but later in the book it says Harry looked up 'dittany' in One Hundred Magical Herbs and Fungi.

* In Chapter 7, page 122, it says that Harry looked up at the Sorting Stool, there were only three people left to be sorted, Professor McGonagall calls the names of four more people instead.

* On page 123, in the chapter "The Sorting Hat," Nearly Headless Nick says that he hasn't eaten in "nearly four hundred years"; but in the second book, Harry goes to Nick's 500th Deathday Party, meaning that Nearly Headless Nick has been dead for 500 years, not 400.

* On the fourth paragraph of page 133, it says that Hermione lent Harry Quidditch Through the Ages: "She had also lent him Quidditch Through the Ages, which turned out to be a very interesting read." On page 46, paragraph three of QTTA, it says "The most successful Japanese team, The Toyohashi Tengu, narrowly missed a win over Lithuania's Gorodok gargoyles in 1994." However, Harry borrows QTTA in Book 1, which is set in 1991. Thanks, Rajan!

* On page 153 of the hard-cover US version of Sorcerer's Stone, Fred says: "We haven't won [the Quidditch Cup] since Charlie left..." However, according to JKR, Charlie is three years older than Percy (who is in his 5th year at the time), so Charlie should still have been in Hogwarts the year before. This makes Fred's statement "We haven't won since last year!"

* On page 236 of the US hardback version of Harry Potter and the Sorcerer's Stone, it reads: "Wednesday night found Hermione and Harry sitting alone in the common room... The clock on the wall had just chimed midnight when the portrait hole burst open. Ron appeared..." But on page 133, it says: "They had to study the night skies through their telescopes every Wednesday at midnight..." So are they cutting class to discuss Norbert?

* On pages 274-275 of the hardback American edition of Sorcerer's Stone, the trio, who are coming from Gryffindor Tower, go up two flights of stairs to get to the third floor. Gryffindor Tower is on the 7th floor, so they should have gone down, not up.

* At the beginning of the chess match, Ron is the knight in the giant chess set. However, it later says that he had to 'move ahead one' so the Queen could take him, opening the path for Harry to checkmate the king. If he was a knight, he could only move 1) ahead one, sideways two, or 2) ahead two, sideways one, like an "L."

* On pages 297 and 302 in the paperback version of Sorcerer's Stone, Dumbledore said that he and Hermione's owl crossed in mid-air. However, on page 302, Hermione said that they ran into Dumbledore on the way to the Owlery to send him the owl.

* On page 205 of the UK SS, Ron says, "Well Harry, you take the place of that bishop, and Hermione, you go next to him instead of that castle." But the castle is next to the knight, not the bishop.

Book 2 Mistakes

* On page 4, the day of Harry's birthday, Rowling says, "and then, exactly a year ago, Hogwarts had written to Harry..." but they had actually written before Harry's eleventh birthday. He'd been receiving them before, he just never had the chance to read one. So technically he had been written to before his eleventh birthday.

* On page 95, it states that Nearly Headless Nick "took several deep breaths, and then said, in a far calmer tone, 'So what's bothering you?'" However, on page 506 of GOF, Myrtle says that ghosts do not breathe: "When I can't ...when I haven't...not for ages..."

* On page 102 of the American COS: "Several (freshly caught Cornish pixies) shot through the window, showering the back row with broken glass." The glass would have splintered outward, not back into the classroom.

* In COS, on page 119 of the American version, it states, "...Harry was dragging his feet along the SECOND floor corridor to Lockhart's office. He gritted his teeth and knocked." However, on page 141, after Mrs. Norris is found petrified on the second floor, Lockhart urges Professor Dumbledore to use his office to examine her, saying that it is just upstairs. That would mean that his office is on the THIRD floor, not the second.

* (NOTE: This mistake applies only to the US versions.) When Professor McGonagall took Harry to Professor Dumbledore's office, the password was "lemon drop," but then in the fourth book when he's going to tell Dumbledore about Mr. Crouch in the forest it says "...five minutes later he was hurtling towards a stone gargoyle standing half way along an empty corridor. 'Sher-sherbet lemon,' he panted at it. This was the password to the hidden staircase to Dumbledore's office- or at least it had been two years ago."

* The chapter picture for "The Rogue Bludger" shows Harry's left arm deboned, but in the story, his right arm has been deboned.

* At the end of the second book Dumbledore tells Harry that Lord Voldemort is the last remaining ancestor of Salazar Slytherin. But it should say that Lord Voldemort is the last remaining descendant of Salazar Slytherin.

* In the back of the paperback version of Harry Potter and the Chamber of Secrets, on the last page where it gives a preview of the next book, it reads: "Harry Potter has to sneak back to his third year at Hogwarts after accidentally inflating his horrible Aunt Petunia." It should say he inflated his Aunt Marge.

Book 3 Mistakes

* The cover of Prisoner of Azkaban (American version) clearly depicts the night that Harry and Hermione save Sirius and Buckbeak. That night is also supposed to be a full moon, as stated in the book. However, on the back side of the cover, the moon appears to be crescent when it should be a full moon.

* In the UK version of POA, page 45 primarily states that Harry is being waited on by the manager of Flourish and Blotts. The manager takes him to the Divination section and takes down Unfogging the Future. However, after Harry is fixated on the Death Omens book, the manager is suddenly referred to as the "assistant."

* In the US version of Book 3, on page 65, when Mr. Weasley is arguing with Mrs. Weasley at the Leaky Cauldron, he says, "You know what Harry and Ron are like, wandering off by themselves--they've ended up in the Forbidden Forest twice!" Ron has only been in the Forbidden Forest once--to see Aragog in COS.

* In the American version of Prisoner of Azkaban, page 72, first paragraph, it states that "Harry and Ron led the way to the end of the train, past packed compartments, to a carriage that looked quite empty. They loaded the trunks onto it, stowed Hedwig and Crookshanks in the luggage rack, then went back outside..."

On page 74, it states that "Harry, Ron, and Hermione set off down the corridor, looking for an empty compartment, but all were full except for the one at the very end of the train. This one had only one occupant, a man sitting fast asleep next to the window."

They had just put their belongings into an empty compartment, so they didn't need to look for another.

On page 76, it states, "A faint, tinny sort of whistle was coming from somewhere. They looked all around the compartment. 'It's coming from your trunk, Harry,' said Ron, standing up and reaching into the luggage rack."

Their trunks couldn't have been in that compartment as they had stowed them in another one. Thanks, Genevieve!

* In Harry Potter and the Prisoner of Azkaban, American paperback version, page 186, paragraph 10, there are no end quotes when Professor Lupin is talking. It says, "'They planted the Whomping Willow the same year that I arrived at Hogwarts. People used to play a game, trying to get near enough to touch the trunk. In the end, a boy called Davey Gudgeon nearly lost an eye, and we were forbidden to go near it. No broomstick would have a chance."

* Prisoner of Azkaban, UK edition: On page 242, it says, "Harry felt strangely unreal, and even more so when he saw Buckbeak a few yards away, tethered to a tree behind Hagrid's pumpkin patch." Later, on page 293, however, it says, "Harry began to fumble with the rope tying Buckbeak to the fence." Here Buckbeak is tied to a fence, not a tree.

* Throughout the series, the future Hufflepuff prefect is referred to as "Ernie Macmillan." However, on page 244 of the American hardcover edition of POA, his last name is spelled "McMillan."

* It says on page 250 (American hardback) and page 185 (UK edition), Chapter 13, that all of the players on the Ravenclaw Quidditch team ride on Cleansweep Sevens. However, on page 254 (American) and page 188 (UK) it states that Wood told Harry that Cho Chang (Ravenclaw Seeker) rides a Comet Two Sixty.

* On page 324, it says that after his exam with Professor Trelawney, "Harry got up, picked up his bag and turned to go." But when Professor Trelawney began her prediction, the book then says, "Her eyes started to roll. Harry sat there in a panic." How could Harry be sitting when it states that he got up right before Professor Trelawney began her prediction?

* On page 341 (American Hardback edition) it says "Ron crawled to the four-poster and collapsed onto it." But then when Professor Lupin comes in, it says, "His eyes flickered over Ron, lying on the floor." This cannot be, as Ron is lying on the bed.

* In the American version of Prisoner Of Azkaban, page 380, when the group is exiting the Whomping Willow, it states: "Black saw Snape up through the hole, then stood back for Hermione and Harry to pass."

But then on page 408, after Harry and Hermione turned back time and are watching their other selves, "They saw Lupin, Ron, and Pettigrew clambering awkwardly out of the hole in the roots. Then came Hermione...then the unconscious Snape, drifting weirdly upward. Next came Harry and Black."

The order is different. The first time, it's Snape, Harry, Hermione, and Sirius. The second time, it's Hermione, Snape, Harry, and Sirius.

* Page 400 states: "Hagrid turned around and headed back into his cabin, leaving the back door ajar." This allows Harry and Hermione to hear the conversation inside. Then, on page 402, it says: "Hagrid's back door had opened with a bang." How can it open again, since it was never closed?