The Significance of Seven

In the 13th century, Arithmancer Bridget Wenlock came up with a fascinating new theorem which exposed the magical properties of the number seven. The number permeates the Harry Potter septet of books, cropping up in all sorts of interesting places: we’ve laid out some of our favourites below...

Seven books in the series
Seven gold Galleons for Harry’s wand
Seven Weasley children
Seven floors of Hogwarts
Seven players in a Quidditch team
Seven obstacles guarding the Philosopher’s Stone
Slytherin wins House Championship seven years in a row
Seven hidden passageways displayed on Marauder’s Map
Seven keyholes on Professor Moody’s trunk
Seven Sickles: the price of Fred and George’s Canary Creams
Seven socks owned by Dobby
Seven years old: the age Unicorns turn pure white
Seventh level of the Ministry of Magic: the Magical Games dept.
Seventh year at Hogwarts: James and Lily become an item
Seven O.W.L.s each for Harry and Ron
Seven questions Bellatrix poses to Severus in Spinner’s End
Seven Horcruxes containing fragments of Voldemort’s soul
Seven people disguised as Harry Potter flying through the sky
Seven: the age by which experts agree magic will have revealed itself
Seven hours Harry spends surveilling the Ministry’s entrance
Seven Defence Against the Dark Arts teachers in the series

Seven: the most powerfully magical number

Lucky Seven

We added up every use of the words ‘Seven’ and ‘Seventh’ in the seven books to see how many times they are used. This does not include chapter or page numbers, numbers containing seven (e.g. ‘one hundred and seven’, ‘seventy’) or plurals (‘sevens’)

16 in Harry Potter and the Philosopher’s Stone
14 x ‘Seven’, 2 x ‘Seventh’

15 in Harry Potter and the Chamber of Secrets
14 x ‘Seven’, 1 x ‘Seventh’

14 in Harry Potter and the Prisoner of Azkaban
8 x ‘Seven’, 6 x ‘Seventh’

22 in Harry Potter and the Goblet of Fire
18 x ‘Seven’, 4 x ‘Seventh’

35 in Harry Potter and the Order of the Phoenix 19 x ‘Seven’, 16 x ‘Seventh’

40 in Harry Potter and the Half-Blood Prince
19 x ‘Seven’, 21 x ‘Seventh’

17 in Harry Potter and the Deathly Hallows
16 x ‘Seven’, 1 x ‘Seventh’

Total 159
108 x ‘Seven’
51 x ‘Seventh’