"Oh, it's wonderful! It's my favourite subject!"
—Hermione Granger in her third year.

Arithmancy is an elective subject offered from the third year on at Hogwarts School of Witchcraft and Wizardry as well as at Ilvermorny School of Witchcraft and Wizardry.[1] During the 1990s at least, the class was taught by Professor Septima Vector[1] in Classroom 7A, on the Hogwarts castle's seventh floor.[2]

Little is known about the class, but the study of Arithmancy has been described as "predicting the future using numbers," with "bit of numerology" as well.[3]

Class information

Homework assignments, which included writing essays, required the consultation and/or composition of complicated number charts.[1]

Arithmancy was Hermione Granger's favourite subject at Hogwarts. She once told Harry Potter it was "wonderful" when he remarked that her challenging homework looked "terrible."[1] However, one of her roommates said that, in her opinion, it was difficult, and by far preferred Care of Magical Creatures.

Another subject, Advanced Arithmancy Studies, was taught at Hogwarts, presumably to the most intelligent and brilliant students. It may have been taught by Professor Vector also, and the Advanced Arithmancy Studies classroom was located on the first floor of the Hogwarts Turris Magnus in Hogwarts Castle.

An O.W.L. in this subject was necessary to apply for a Curse-Breaker position at Gringotts.[4]

Required textbooks

Known professors


Passing Grades

Fail Grades

Known O.W.L.s

Known N.E.W.T.s

Behind the scenes


Notes and references

Professors: Septima Vector
Known Arithmancers: Bridget Wenlock
Textbooks: Numerology and Grammatica · New Theory of Numerology
Arithmancy at Hogwarts: Arithmancy (class) · Classroom 7A · Advanced Arithmancy Studies
Hogwarts Curriculum
Core classes Astronomy · Charms · Defence Against the Dark Arts · Herbology · History of Magic · Potions · Transfiguration
Elective classes Alchemy · Arithmancy · Care of Magical Creatures · Divination · Muggle Studies · Study of Ancient Runes
Extra-curricular classes Apparition · Advanced Arithmancy Studies · Ancient Studies · Art · Flying · Ghoul Studies · Magical Theory · Muggle Art · Muggle Music · Music · Xylomancy
First year exams · Second year exams · Third year exams · Fourth year exams ·
Ordinary Wizarding Level · Nastily Exhausting Wizarding Test
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