"...isn't seven the most powerfully magical number, wouldn't seven--?"
Tom Riddle discusses the power of the number seven[src]

Bridget Wenlock

Seven is the most powerful magical number[1], based on centuries of mythology, science, and mathematics, and therefore has a very important role in the wizarding world. Arithmancer Bridget Wenlock was the first to note this through a theorem which exposed the magical properties of the number seven.[2]


The Arithmancer, Bridget Wenlock (12021285) was the first witch to establish the magical properties of the number seven.[2] She wrote her ground-breaking theorem on the back of a sugar packet, using her usual invisible ink. She then proceeded to send her cousin a letter, forgot where she wrote the theorem, and thought it was on the envelope. She hunted down the envelope and intercepted it at her cousin's house, where she learned her mistake.[3]

Seven is the age by which most experts believe that magic will reveal itself in a wizard or witch.[4]

Seven seen in the wizarding world





  • Children go to school at Hogwarts for seven years.
  • There are seven floors at Hogwarts.
  • There are seven Core classes, which are taught at Hogwarts:
  1. Astronomy
  2. Charms
  3. Defence Against the Dark Arts
  4. Herbology
  5. History of Magic
  6. Potions
  7. Transfiguration






  • In 1996, Bellatrix Lestrange asked Severus Snape seven questions regarding to his loyalty to Lord Voldemort:
    1. Where was he when Voldemort fell
    2. Why did he never make any attempt to find Voldemort
    3. What has he been doing during the period between Voldemort's fall and rebirth
    4. Why did he stop Voldemort from procuring the Philosopher's Stone
    5. Why did he not return to Voldemort immediately when all Death Eaters were summoned
    6. Where was he during the Battle of the Department of Mysteries
    7. Why is Harry Potter still alive despite being under his mercy for five years
  • Harry Potter's chocolate frog card stated that he was famous for seven reasons:
    1. Being the first and only known wizard to have survived the killing curse.
    2. Being the youngest seeker in a century, having gained a spot on the Hogwarts Gryffindor Quidditch team in 1991 at only eleven years old.
    3. Finding and opening Salazar Slytherin's Chamber of Secrets in his second school year and defeating the monster within, which was a Basilisk.
    4. Being the youngest competitor of the Triwizard Tournament and winner of said tournament in 1995.
    5. Being the only known Gryffindor student that can speak Parseltongue.
    6. Being the last master of death to have united the three Deathly Hallows
    7. Defeating the most dangerous dark wizard of all time, Lord Voldemort, in 1998.
  • Nicolas Flamel is seven years older than his wife.
  • During Harry's hearing in the Ministry (in 1995), Dumbledore states that clause 7 of the Decree for Reasonable Restriction of Underage Sorcery allows the use of magic in life-threatening situations.

Behind the scenes


  • The first book was released in 1997, and the final book was released in 2007.
  • The epilogue itself is set in 2017.
  • Many fans expected Harry Potter and the Deathly Hallows (the seventh book) to be released on 07/07/2007, which also happened to be a Saturday, the day upon which Harry Potter books had previously been released. However, it was released on July 21st of that year instead, two weeks later. It is thought that the more 'magical' date was rejected due to it also being the second anniversary of the 7/7 London Bombings in 2005. (21 is still a multiple of 7 though.)
  • On 7 August, the Harry Potter series won seven awards at the 2011 Teen Choice Awards for Deathly Hallows: Part 1 and Part 2.
  • The Battle of Hogwarts in on 2 May, the 2nd day of the 5th month. 2 +5 = 7
  • The first film in the Fantastic Beasts and Where to Find Them trilogy is set 70 years before the Harry Potter series.




  • The number on the back of Harry Potter's Quidditch robes in the films is seven (this could be a reference to the fact that usually the best player/captain in a football team, has the number 7 shirt).
  • J. K. Rowling stated in interview that she chose to write seven books in total because she spent seven years in secondary school. Also, she wanted Harry to come of age at seventeen because it "just seems a good number for a wizard to come of age."
  • In the seventh Harry Potter book, J.K. split the dedication in seven parts.
  • There were seven clues and seven opportunities to sign up and register for the Pottermore beta. The first clue was on 31 July 2011 (Harry's birthday) and the final was 6 August 2011. A clue was released each day and each clue was from a book in the series corresponding to the day. For example, day one's clue was from Philosopher's Stone and the final clue was from Deathly Hallows.
  • In Harry's copy of Fantastic Beasts and Where to Find Them, he wrote in the Pixie section for the classification, and put seven X's: "or XXXXXXX if you're Lockhart."
  • Seven is also a unique number, being the highest, single-digit prime number.


External links

WP favicon Seven on Wikipedia

Notes and references

  1. Harry Potter and the Half-Blood Prince, Chapter 23 (Horcruxes)
  2. 2.0 2.1 Wizard of the Month
  3. Wonderbook: Book of Spells
  4. Harry Potter and the Deathly Hallows, Chapter 11 (The Bribe)
  5. Wonderbook: Book of Potions - The first Championship was known held in 1407, which is a multiple of seven. Since the event was held every seven years, unless there were irregularities, every subsequent Championship was also held in a year divisible by seven.
  6. Harry Potter and the Philosopher's Stone, Chapter 16 (Through the Trapdoor)
  7. Michael Berendt's website.
  8. SnitchSeeker - J.K. Rowling Talks Harry Potter and the Deathly Hallows: Part 2
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