Birthdays

A birthday is the annual celebration of the day a witch or wizard was born. In the Wizarding World, birthdays are marked with customs similar to those in the Muggle world, including parties, cakes, and the giving of gifts. The most significant birthday for a young witch or wizard in Great Britain is their seventeenth, as this is when they legally come of age. Upon turning seventeen, they are permitted to use magic outside of Hogwarts School of Witchcraft and Wizardry and are eligible to obtain a license for Apparition.

Birthday celebrations range from small, private affairs to larger parties.

• Gifts: It is customary to give presents. Gifts can range from simple items like sweets and books to more elaborate magical objects. Harry Potter's birthdays are notable as he rarely received proper presents or acknowledgement before entering the Wizarding World.
• Cakes: Birthday cakes, often magically enhanced, are a common feature. Rubeus Hagrid famously brought Harry Potter a slightly squashed, sticky chocolate cake for his eleventh birthday, the first one he had ever received. Molly Weasley is also known for baking impressive cakes for her children and for Harry.
• Parties: Celebrations can be held at home, such as at The Burrow. Harry Potter's seventeenth birthday party was a significant event, although it was overshadowed by the looming threat of Lord Voldemort and was ultimately cut short by an attack from Death Eaters.
• Howlers: In a less common and unpleasant tradition, Neville Longbottom once received a Howler from his grandmother after she learned he had lost the list of passwords to Gryffindor Tower, an event occurring around the time of his birthday.

Several birthdays are pivotal to the plot of the series, particularly those of Harry Potter.

• Harry Potter's Eleventh Birthday (31 July 1991): This is arguably the most important birthday in the series. Rubeus Hagrid finds Harry at the Hut-on-the-Rock, tells him he is a wizard, and gives him his Hogwarts letter. This event marks Harry's entry into the Wizarding World.
• Harry Potter's Twelfth Birthday (31 July 1992): Dobby the house-elf visits Harry in his room at Number Four, Privet Drive, leading to a disastrous pudding incident. Harry is subsequently locked in his room by the Dursleys. He is later rescued by Ron Weasley, Fred Weasley, and George Weasley in their father's Enchanted Ford Anglia.
• Harry Potter's Thirteenth Birthday (31 July 1993): For the first time, Harry receives birthday cards and presents from his friends in the Wizarding World, including a Pocket Sneakoscope from Ron, a Broomstick Servicing Kit from Hermione Granger, and a copy of The Monster Book of Monsters from Hagrid.
• Harry Potter's Fourteenth Birthday (31 July 1994): Harry receives four birthday cakes from Ron, Hermione, Hagrid, and Sirius Black. His birthday occurs while he is staying at The Burrow before the Quidditch World Cup.
• Harry Potter's Sixteenth Birthday (31 July 1996): Harry celebrates his birthday at The Burrow with the Weasley family and guests Remus Lupin and Nymphadora Tonks. The mood is somber due to the ongoing Second Wizarding War.
• Harry Potter's Seventeenth Birthday (31 July 1997): A crucial day. The Order of the Phoenix's protection over Harry at the Dursleys' home expires. The “Seven Potters” plan is executed just before midnight. A small party is held at The Burrow on his birthday, during which the Minister for Magic, Rufus Scrimgeour, visits to deliver the contents of Albus Dumbledore's will. The party is interrupted by an attack from Death Eaters during Bill Weasley and Fleur Delacour's wedding reception later that evening.
• Neville Longbottom's Birthday (30 July): Neville was born one day before Harry. According to the Prophecy made by Sybill Trelawney, he was the other boy to whom it could have referred, as his parents had also thrice defied Lord Voldemort.
• Tom Riddle's Birthday (31 December): Lord Voldemort's birthday falls on New Year's Eve. Albus Dumbledore notes that he was conceived under the influence of a Love Potion, and thus was incapable of understanding love.
• Dudley Dursley's Eleventh Birthday (23 June 1991): While not a wizard's birthday, it is significant because the family trip to the zoo for his birthday is where Harry first discovers he can speak Parseltongue by communicating with a Boa Constrictor.

• Deathday: A Ghost's “deathday” is the anniversary of the day they died. Nearly Headless Nick celebrates his 500th Deathday with a large party in the Dungeons of Hogwarts on Hallowe'en.

• J.K. Rowling shares her birthday with her most famous character, Harry Potter. Both were born on 31 July. (J.K. Rowling interview)
• In the film adaptation of Harry Potter and the Philosopher's Stone, Hagrid's cake for Harry is famously misspelled as “Happee Birthdae Harry.” (film)
• In the film adaptation of Harry Potter and the Half-Blood Prince, Harry's birthday cake at The Burrow is shaped like a Golden Snitch. (film)