Zoë Wanamaker does not appear in this film as Hogwarts' flying instructor, Madam Hooch, as Wanamaker found the salary unsatisfying. Her character was written out by giving Hooch's speaking lines to McGonagall and other characters.
The train station interior used in the film is King's Cross in North London, whereas the exterior shot is actually St. Pancras. The two stations are adjacent to one another, but not the same building. This was done because the architecture of St. Pancras is much more visually appealing.
A cinema manager in Stavanger, Norway reported that the film was making his younger patrons ill. Evidently many children who had overindulged on sweets and popcorn were throwing up when Ron begins vomiting giant slugs. "It is not a particularly fun task for our employees to have to wash away the sick," he said.
A gag from the book is rendered incomprehensible in the film, due to lack of information. While chatting with the Grangers at the bookshop, Mr. Weasley says, "I understand that other Muggles are afraid of you." This is because they are dentists.
A story circulated that Emma Watson broke her left wrist during filming and that you can just see a little bit of the cast under her sleeve in some scenes, but it turned out to be false.
The tapestries hanging in the Gryffindor Common Room are copies of the "Lady and the Unicorn" series, a set of 16th century tapestries that are now displayed in the Cluny Museum in Paris.
The Weasley's car is a Ford Anglia. This is actually the same color and model car that author J.K. Rowling and her best friend from school used to ride around in when they were younger. She used the car for the book, and later the movie, out of her fond memories driving in it.
Through advance ticket sales at Odeon cinemas, the film generated more than £1 million (roughly 200,000 tickets) before its release in the UK. An additional £8 million was generated through preview showings at UK cinemas (both Odeon and non-Odeon).
On an episode of Have I Got News for You broadcast around this film's release, the panelists discuss an article claiming that the Russian President (later Premier) Vladimir Putin was deeply disturbed and offended that Dobby the House elf seemed to have been created in his image. There is an undeniable resemblance either way.
In order to create a realistic image of the floating set of needles (knitting in The Burrow), one of the crew coerced his mother to let them film her for several hours as she did her own knitting.
Due to schedule conflicts, John Williams was not able to deliver a fully elaborated score. Composer-arranger William Ross was hired to adapt Williams' material to complete the film's score and was subsequently conducting the orchestra during the recording sessions.
The film earned over $88 million in the US on its opening weekend, which at the time placed it third in the all-time biggest opening behind Spider-Man and Harry Potter and the Sorcerer's Stone.
Daniel Radcliffe was initially only offered £125,000 (approximately US $181,500) for this film. The actors' union, Equity, stepped in and negotiated new terms which increased his salary to roughly £2,000,000 (US $3,000,000).
The title used by the crew to disguise the shoot (and printed on the clapper boards) was "Incident on 57th Street", the title of a 1973 Bruce Springsteen song.
Young Hagrid is played by Martin Bayfield, who stands in for Robbie Coltrane as his height double in all the Potter films. His voice is dubbed by Coltrane, for the sake of consistency.
When Hagrid is escorting Harry out of Knockturn Alley, and again when Lockhart turns to show his other profile to the photographer, hardcover editions of Harry Potter books can be seen on the shelves.
The opal necklace, which plays an important role in Harry Potter and the Half-Blood Prince, can briefly be glimpsed inside a display case in Borgin and Burkes' shop in Knockturn Alley when Harry first enters.
During production, Emma Watson frequently brought her pet hamster Millie on set. Unfortunately, Millie passed away shortly after shooting began. The set department for the film created a specially-made hamster coffin, complete with velvet lining and the name "Millie" engraved on the top. "I don't think a hamster has ever had a better send-off." Watson said.
During the Quidditch Match, some of the music used while Harry and Draco chase the Golden Snitch was used during the speeder chase scene in Star Wars: Attack of the Clones. John Williams did both scores.
Many people think that Professor Gilderoy Lockhart is a character based on JK Rowling's ex-husband, but she has said on her official website that Lockhart is based in an egocentric person that she really dislikes, but he is not her ex-husband.
The camera used by Colin Creevey is an Argus C3 Matchmatic, a cheap and very popular 35mm rangefinder camera manufactured in the USA from 1939 to 1966.
Although based on the second shortest book, this is the longest of the films. Harry Potter and the Order of the Phoenix, which is based on the longest book, is the second shortest of the films.
Although the subplot which involved Percy Weasley and Penelope Clearwater (when Ginny discovered them kissing and promised not to tell anybody) was cut, whilst Nearly Headless Nick is on his way to the Great Hall, he does say: "Hello Percy, Ms Clearwater," to the couple as they walk out.
When Hagrid charges into Dumbledore's office to defend Harry, he is carrying a dead rooster in his hands. This is in reference to a scene in the book (cut from the movie) where Hagrid finds all the roosters dead. The sound of a cock-crow is fatal to a basilisk.
The script originally said that Hermione would hug Harry and Ron in the final scene. As the then 11-year-old Emma Watson was embarrassed about having to hug the boys in front of the entire cast, Chris Columbus allowed her to change the scene so that Hermione just hugs Harry then starts to hug Ron but the two get embarrassed and resolve to only shake hands. Watson also stated in a recent interview that she kept letting Daniel Radcliffe go too quickly, so the film was "frozen" for a few seconds to make the hug look like it lasted longer than it actually did. Her hesitation with Ron is also taken by fans as a precursor to the relationship that will develop between the two characters.
When Lucius Malfoy tries to curse Harry at the end, he mutters,"Avada..." As mentioned in the 4th book, this is the beginning of an Unforgivable Curse named Avada Kedavra, or the killing curse.
Foreign language translations had to change Tom Marvolo Riddle's name so that an appropriate anagram could be formed from "I am Lord Voldemort." In Spanish, his name became "Tom Sorvolo Ryddle," which transforms into "Soy Lord Voldemort." In French, his name is "Tom Elvis Jedusor," which becomes "Je suis Voldemort." In Dutch, his name is "Marten Asmodom Vilijn" which is an anagram for "Mijn naam is Voldemort". In Turkish the name is "Tom Marvoldo Riddle" which makes up "Adim Lord Voldemort". In Brazilian Portuguese the name is "Tom Servolo Riddle" which makes up "Eis Lord Voldemort". In Danish, his name is "Romeo G. Detlev Jr." which makes up "Jeg er Voldemort". In Italian his name is "Tom Orvoloson Riddle", which makes up "Son io Lord Voldemort". In Swedish his name is "Tom Gus Mervolo Dolder", which makes up "Ego sum Lord Voldemort".