Mistakes in the Harry Potter books

Below is a list of all the mistakes that occur in the Harry Potter book series.

Harry Potter and the Philosopher's Stone

 * In this book, Harry states his 11th birthday was July 31st, a Tuesday. But in 1991, that date was a Wednesday.
 * While being sorted into houses, Harry looks up at the Sorting Stool, and there are only three people left to be sorted. Professor McGonagall then calls out the names of four more kids. It is possible that Harry missed out on one.
 * Harry buys the book "One Thousand Magical Herbs and Fungi", but later, he looks up "dittany" in "One Hundred Magical Herbs and Fungi". The title changes.
 * The book mentions that the Boa Constrictor at the zoo winked at Harry. Snakes do not have eyelids at all, so it is impossible for them to wink.
 * On Harry's Hogwarts list of School Supplies, "1 Wand" is listed twice, as both the first and last item on the list (fixed in later editions).
 * Much of the first chapter talks about wizards celebrating the fall of Voldemort all day long, yet Harry's family was attacked at nighttime. Unless it took Hagrid 24 hours to get Harry from his parents' ruined house to Little Whinging, this does not make sense.
 * It states in the Hogwarts letter that you can bring an owl, toad, or cat. Ron brings his rat Scabbers.

Harry Potter and the Chamber of Secrets

 * The Hogwarts' equipment list mentions the Lockhart book "Wanderings With Werewolves," but later, Lockhart refers to the book as "Weekend With a Werewolf".
 * After Harry, Ron, Fred, and George arrive at the Burrow after getting Harry, Mrs. Weasley shouts at Fred first. "You will not," snapped Mrs. Weasley. Then she says "And you two," glaring at Ron and Fred. It should say George, for she has already yelled at Fred. (Fixed in later editions)
 * Dumbledore tells Harry at the end that Lord Voldemort is the last remaining ancestor of Salazar Slytherin. But ancestors are in the past - he means Voldemort is the last descendant of Salazar Slytherin. Not a mistake Dumbledore would have made. (Corrected in later printings.)
 * Hermione says Moaning Myrtle haunts the bathroom on the first floor. However, when Harry sees the writing on the wall outside her bathroom, he is on the second floor. (This is explained by the fact that in the UK, the ground floor is the floor on which the entrances are, and the floor above it is the first floor.)
 * Harry, Ron and Hermione go to Nearly Headless Nick's 500th deathday party. However, in the first book, at the start of term feast, he says he has not eaten for nearly 400 years, which would imply that this is how long he has been dead.
 * There is a scene after Ron walks out of Moaning Myrtle's bathroom where Percy takes five points from Gryffindor. However, in Order of the Phoenix, at the beginning of the chapter "Snape's Worst Memory," it is clearly stated by Ernie Macmillan and Ron that prefects cannot dock points. Correction: This is corrected in later editions, Ernie Macmillan says that prefects cannot dock points from each other.
 * When Harry is viewing the memory from Tom Riddle's diary, Tom Riddle says to Hagrid at one point, "The dead girl's parents will be here tomorrow." It is stated elsewhere in the book that Myrtle is Muggle-born. Muggles cannot enter Hogwarts. However, it is possible that an exception was made for them (the Muggle-Repelling Charm could be lifted a day or two, for this reason).
 * When Malfoy calls Hermione a 'Mud-Blood', Ron later explains to Harry that this is a "very awful and rude name for muggle-born wizards". Later, when McGonagall is explaining about the attacks on students she says "last year, a mud-blood was killed!". Professor McGonagall would not refer to a student using a "very awful and rude name for muggle-born wizards". McGonagall would have said half-blood or muggle-born, as she is not the type who would say such a thing about a student.

Harry Potter and the Prisoner of Azkaban

 * Given that Remus Lupin had a transformation sometime after Halloween but before the following weekend (the day of the Gryffindor-Hufflepuff match), the full moon would have had to be sometime in the first week of November, probably the 4th or 5th of November as he was absent from class on the Friday before the match. As the full moon occurs every 29-30 days, by that time frame the December and January full moons would also have occured sometime around the 3rd-5th of those months. Therefore a full moon during the Christmas Eve to Boxing day period is not possible. Yet Dumbledore explains to Trelawney that Lupin's absence from the Christmas dinner is that he is not well again - implying either a transformation or post-transformation exhaustion, especially as Snape is mentioned as having brewed his potion for him.
 * Before Harry and Hermione go back in time, it mentions that Buckbeak is tied to a tree. But when they go back in time, Buckbeak is tied to a fence.
 * When Harry is buying his books at Flourish and Blotts, it mentions that he is being served by the manager. But when Harry was staring at the book 'Death Omens', it says that he is being served by the assistant of the store.
 * The length of time Sirius has known Pettigrew is hiding at Hogwarts is inconsistent. From Mr. Weasley's conversation at the Leaky Cauldron in chapter four, Sirius has known about it for several months. But in the Shrieking Shack in chapter eighteen, Sirius says that he first learned about it the night he escaped from Azkaban. (This is incorrect, Mr. Weasley is still assuming Sirius is after Harry, not Pettigrew, and Sirius' night mumbles of "He's at Hogwarts".)
 * On the Marauder's Map, the possessive form of "Marauders" is incorrect. Since the Marauders were a group of students (thus, the term is plural), it should be "Marauders' Map."
 * Note that the book was written before it became a commonplace term to refer to the group as the Marauders; nowhere in this book are they referred to as such.
 * Also note that the title might reflect that it is a Map for use by a marauder, as opposed to a map made by the group called Marauders.
 * In June, Fred and George Weasley find out they have scraped "a few O.W.L.s apiece". However, in subsequent books, it is firmly established that O.W.L. results are sent home by owl and are not received until August.
 * It says "Ron crawled to the four-poster and collapsed onto it". But when Professor Lupin comes in, it says "his eyes flickered over Ron, lying on the floor". This could not be, as Ron should still be on the bed. Crookshanks was on the bed, and 'on the floor beside him.... was Ron' Ron moves from this position to 'protect' Harry. 'If you want to kill Harry, you'll have to kill us to' at this point he is standing, 'clinging painfully to Harry to stay upright'.
 * Mr. Weasley says that Ron and Harry have ended up in the Forbidden Forest twice. But only Harry has been in the forest twice. Ron went once to see Aragog with Harry in Chamber of Secrets, but the other time Harry went was for detention in Harry Potter and the Philosopher's Stone, and Ron wasn't there (he was in the movie, but not the book).
 * When Harry and Hermione leave from the hospital wing using the Time-Turner, Dumbledore says it is ten minutes until midnight, but on the way back to the ward after they rescue Sirius, they hear Dumbledore say to the other versions of them that it is five minutes to midnight. (This could mean that they took five minutes extra to return to the hospital wing)
 * Chapter sixteen (Professor Trelawney's Prediction) takes place in June 1994. In the beginning of that chapter, Harry Potter reads a note from Hagrid and says, 'Buckbeak's appeal — it's set for the sixth.' The night after the Hippogriff's appeal, Remus Lupin is forced into a werewolf form by the full moon, which means that this happened on the night of June 6th, 1994. The web page HP-Lexicon.org also backs this up. However, a brief look at lunar phase calendar sites such as 1994 and lunar phases in 1994 definitely shows June 9, 1994, as a new-moon night, which means that a full moon could not possibly rise three days earlier.
 * On the American version of the cover, the front art is the night that Harry and Hermione save Sirius and Buckbeak. However on the back side of the cover, the moon is crescent when it should be a full moon.
 * When Lupin looks at the Marauder's Map and sees Harry, Hermione, and Ron going to Hagrid's hut for Buckbeak's appeal, the Harry and Hermione from the future are not far behind them. Doesn't this mean that Lupin would have seen two sets of Harry and Hermione on the map? Also Snape saw the map and would have seen the same thing. (Professor Lupin claims the map never lies.)
 * The cover depicts Harry and Hermoine riding Buckbeak. Harry's legs are shown to be in front of Buckbeak's wings. However, when Harry was in Care of Magical Creatures and rode Buckbeak for the first time, Hagrid had told him to sit behind the wing joint (as he did in the movie).
 * Sirius Black says that Voldemort has been in hiding for fifteen years. He's actually been in hiding for twelve years (almost thirteen at the time that he says it), about the same amount of time since Black was imprisoned. Voldemort went into hiding right after he was ripped from his body after failing to kill Harry. Of course, Black could just be rounding off to an approximated number (fifteen years), but this seems unlikely since he keeps talking about being in Azkaban for twelve years, being that the two time frames are almost exactly the same. Sirius also says to Pettigrew 'you haven't been hiding from me for 12 years, you've been hiding from Voldemorts old supporters'.
 * Hermione's use of a Time-turner to get to all her classes indicates that it is not possible to take all twelve subjects (the seven compulsory subjects plus all five electives) without one and McGonagall's having to write multiple letters to the Ministry to obtain one indicates that this is not something that is accomplised easily or done regularly for students. These overlapping class times in Prisoner of Azkaban is inconsistent with the revelation in Chamber of Secrets that both Bill and Percy Weasley obtained twelve O.W.L.s as they too would have needed a time-turner for three years to make it to all the classes. Also given that an academically brilliant student like Hermione couldn't keep up with that workload for 1 year, it seems unlikely that both Bill and Percy could have managed it for three years, especially with the addition of prefect duties in their respective O.W.L years.

Harry Potter and the Goblet of Fire

 * Towards the end of the book when Voldemort puts the Imperius Curse on Harry the book says "For the third time in his life," when towards the middle of the book it states Harry had the Impurius Curse put on him four times by Moody (Crouch).
 * Harry's fourteenth birthday is on July 31, 1994 but in his letter to Sirius at the beginning of the book he mentions that his cousin Dudley got really angry and chucked his PlayStation out of the window. The PlayStation wasn't released in Europe until September 29, 1995. It could not have been imported either, because the PlayStation wasn't released in Japan until December 3, 1994. However, it is possible that the Dursley's had signed up to be product tester, which would mean that they would recieve the product (in this case, a playstation, and a couple games) months before the product was released.
 * At the ending of the book Harry, Hermione and Ron travel on the "carts without a horse" and then Harry cannot see the thestrals, even though he has already seen Cedric and Lily die. The reason Rowling has given for this is that Cedric's death hasn't yet fully sunk into Harry's mind.
 * In what is now known as the "Wand Order Mistake," when Harry and Lord Voldemort's wands engage in Priori Incantatem while in the graveyard James Potter exits the wand before Lily Potter. It has always been said that James died first as he was trying to give Lily and Harry time to flee, and since victims of Lord Voldemort were exiting the wand in reverse order of being killed it was thought to have been a clue from J.K. Rowling. Rowling later said that "late night writer's fatigue" was the reason and the error has been fixed in future editions.
 * In the first task, nowhere has it been stated that one could not retrieve the Golden Egg through the use of a Summoning Charm, but none of the champions even attempted this most simple system to do so. However, it is stated that the first task was designed to test the champions' daring and courage; thus, using a Summoning Charm would be too easy – almost to the point of cheating. It is possible that use of this spell would have resulted in a bottom score, or that there were enchantments on the eggs to prevent summoning.
 * During the meeting between Fudge, Dumbledore and Moody, Fudge is mistakenly referred to as both "Crouch" and also as his first name, "Cornelius."
 * In the European and Canadian versions of the book, Snape shouts "Ten points from Hufflepuff, Fawcett! And ten points from Ravenclaw too, Stebbins!". Really, Fawcett is in Ravenclaw, and Stebbins is in Hufflepuff. The American version corrects this error, but in a deleted scene from the film, included in the uncut DVD, Fawcett is again the Hufflepuff, and Stebbins the Ravenclaw.
 * When the Death Eaters meet again at Voldemort's rebirth, Voldemort passes the gap for two people between Lucius Malfoy and another Death Eater and states that "the Lestranges are missing because they went to Azkaban rather than renounce him". When he passes the gap large enough for 6 people, Voldemort states "one is too cowardly to return (Igor Karkaroff), one has left him forever (Severus Snape), one is his most faithful servant (Barty Crouch Jr. disguised as Mad Eye Moody), and that three are dead in his service (Evan Rosier and two others). There are two mistakes. First of all, Bellatrix Lestrange, her husband Rodolphus, and her brother in law Rabastan all went to Azkaban so there should have been a gap large enough for three people. Second of all, since no one had broken out of Azkaban, how would Dolohov, Mulciber, Travers, and Rookwood be back in the circle? As shown by this book and later books, all four were still alive.
 * In Quidditch Through the Ages, it says that the first ever World Cup was in 1473, with a match being held every 4 years. Yet the World Cup in 1994 is number 422. There cannot be 422 world cups in 521 years with a four-year gap in between. Calculated correctly, the World Cup that the Weasleys, Hermione, and Harry attend is actually the 131st, and it should have been held in 1993.
 * Before the third task starts, Molly Weasley reminisces about the gamekeeper before Hagrid, named Ogg. But in other books, it is implied that Hagrid has held that post since his expulsion from school in 1943. Since Hagrid's years as gamekeeper appear to overlap Molly's years at school, it seems unlikely that she knew a previous one. Either that or Hagrid originally started off as Ogg's assisstant.
 * When Fred and George bet on the Quidditch match with Bagman, it says Fred put the paper with their wages in his robes, but Fred was wearing Muggle clothing.
 * In the beginning, it says that Harry thought that for one hour last year he'd be staying with Sirius, but in the third book, he only thought he'd be staying with Sirius for a half an hour.
 * In chapter 35, the book says '"The Imperius Curse," Moody said.' However, the Polyjuice Potion has already worn off, so it should be Barty Crouch Jr. speaking.
 * Barty Crouch Sr. mentions that his son got twelve O.W.L.s. Once again this is inconsistent with the time-table clashes from Prisoner of Azkaban. However given Crouch Sr.'s damaged state of mind he could have just been rambling inanely. Either that or with his position in the Ministry, it is possible that he obtained a time-turner for his son.

Harry Potter and the Order of the Phoenix

 * During Harry's hearing, Cornelius said that he blew up his aunt 3 years ago. But 3 years ago was in Harry's second year, and Harry blew up his aunt in his 3rd year.
 * During the meeting in the Hog's Head, Dennis Creevey shows up for the meeting. However, in Harry's fifth year, Dennis would only be a second year, and therefore would not be able to visit Hogsmeade.
 * In chapter 9, when Harry lets Hermione borrow Hedwig, Harry remains bent double until he hears Hermione close the door. However, when he hears Hermione and Hedwig had gone, he hurries across the room and closes the door, but the door had already been closed.
 * In chapter 30 of the American hardcover, Harry and Hermione find seats in the topmost row at the Quidditch match. But when Hagrid comes to tell them about Grawp, he squeezes his way through the row behind them. If Harry and Hermione are in the topmost row, there can't be a row behind them.
 * Harry says that Dobby had left the Malfoys to give him warnings two years ago, but that happened in book two, which was three years ago. Dobby was still employed by the Malfoys when he arrived to warn Harry.
 * When Hagrid returns and begins teaching his class again, he comments that he has been bringing Thestrals for his fifth years' O.W.L.s for years. But he only became a teacher two years ago, in Prisoner of Azkaban.
 * In chapter 37, after Sirius' death, Harry reminisces about when Sirius watched him play Quidditch in Harry's third year. Harry wonders if Sirius had come to see if he was as good a player as James had been, and regrets never having asked him. However, in Prisoner of Azkaban Sirius specifically tells Harry that he did watch him for that exact reason, and that he was as good as his father.
 * During the Ordinary Wizarding Level examinations, Hannah Abbott was doing her transfiguration practical at the same time as Harry Potter. This is odd as the examinations are done by surname, meaning that Hannah should have finished a while ago.

Harry Potter and the Half-Blood Prince

 * On page one-hundred and one of the British version of Harry Potter and the Half-Blood Prince, Ron mentions that Hermione got ten Outstandings and one Exceeds Expectations for Defence Against the Dark Arts giving her a total of eleven O.W.L.s. However, as she dropped both Divination and Muggle Studies in her third year, she couldn't possibly have got eleven O.W.L.s as she was only doing ten subjects - Transfiguration, Charms, Herbology, Potions, Defence Against the Dark Arts, History of Magic, Astronomy, Care of Magical Creatures, Arithmancy and Ancient Runes. Apparently, this error was corrected in later editions.
 * On Harry`s sixteenth birthday, Remus Lupin tells Harry that Ollivander has gone missing. But in Harry Potter and the Deathly Hallows, it said that Ollivander had been in the Malfoys' cellar "a year". However, if he had been captured at the beginning of the sixth book, he would have been held in the cellar for about two years. However, this could mean that Ollivander was held in a seperate place for a year before being moved to Malfoy Manor.
 * In the chapter titled "The Secret Riddle", ". . . Dumbledore entered the room . . . It was a small bare room with nothing in it except an old wardrobe and an iron bedstead." A couple paragraphs later, "Dumbledore drew up the hard wooden chair beside Riddle, so that the pair of them looked rather like a hospital patient and visitor." Of course, since Dumbledore is a wizard, this may not be a mistake at all.
 * Hermione (approximately as tall as Harry) reaches out to pat Hagrid's shoulder, later Harry can only reach as high as his elbow. (It is possible that at the time Hermione patted Hagrid's shoulder Hagrid was seated and when Harry patted Hagrid's elbow, Hagrid was standing.)
 * On page three-hundred and forty-two of the American version of Harry Potter and the Half-Blood Prince, there is a punctuation error when Molly Weasley says "Have a little purkey, or some tooding...I mean-" to Rufus Scrimgeour. There are no quotation marks in front of the have in the statement. This is corrected in the newer editions, however.
 * When talking to Katie Bell about Quidditch, Harry says to her, "you don't need to try out, I've watched you play for five years...", to which Katie replies, "You mustn't start off like that, for all you know, there's someone much better than me out there. Good teams have been ruined before now because Captains just kept playing the old faces, or letting in their friends..." However, there were never any tryouts mentioned in Harry's second or third year, and the same team members played for all three years. In fact, the first tryouts mentioned are in 1995 when they need to get a new Keeper, and this was the only position that changed at the time. In addition, Harry had only watched her play for four years, since Quidditch was cancelled in his fourth year for the Triwizard Tournament.

Harry Potter and the Deathly Hallows

 * Near the end of chapter thirty, it says that the only people left in the Room of Requirement are Harry, Ginny, Mrs. Weasley, Lupin, Fred, George, Bill and Fleur. But on the next page Percy (who had recently entered the room) says sorry to Mr. Weasley, but Mr. Weasley had left the room along with all the other people.
 * When Harry is viewing Snape's memories, he witnesses a scene on Platform 9 3/4 between his mother and aunt Pentunia, in which Petunia tugs her hand out of Lily's grasp. Her hand is then back in Lily's and she tugs it out again.
 * When Harry stuns Umbridge and Yaxley in the courtroom, he "whirls around" to see Dementors approaching Mrs. Cattermole. But Harry was already facing her, having been seated behind Umbridge, Yaxley, and Hermione.
 * When Harry talks to Griphook about breaking into Gringotts, Griphook has the Sword of Gryffindor in his hands. When Harry stands up to leave a few moments later, the sword is now beside Griphook's bed.
 * At the beginning of chapter 2 it says that Harry can't use magic due to not coming of age for 4 days. In chapter 6, days have past since the Battle over Little Whinging but Harry states the trace will break in 4 days.