As you wander the myriad magical hallways of Hogwarts School of Witchcraft and Wizardry during your time in Hogwarts Legacy, you will notice some strange locked doors. These doors, known as Arithmancy Doors, are puzzles. So you’ll have to put your thinking cap on in order to open them. Fortunately, there’s a trick that makes every door much easier to solve. Here’s what you need to know.

How to open Arithmancy Doors

In order to open these doors, you need to understand what’s actually going on. When you press “Reveal” on the door and see a mathematical formula with strange symbols, it usually looks far more complicated than it actually is. Each fantastical creature on the door represents a different number, so you need to mentally replace the creature in the formula with the corresponding number.

After that, simply subtract the two smaller numbers from the central number, and you’ll have your answer. From there, find the left and right dials and rotate the symbols until you get a creature that matches the number of your answer. The left dial corresponds to the top formula, while the right dial will correspond to the bottom formula.

You can find a note that gives you a cipher for all of the animals, but to make things easier, here’s the number every animal represents:

• 0 – Demiguise
• 1 – Unicorn
• 2 – Graphorn
• 3 – Runespoor (Three-headed snake)
• 4 – Fwooper
• 5 – Quintaped (Five-legged creature)
• 6 – Salamander
• 7 – Grindylow (Odd squid)
• 8 – Acromantula
• 9 – Hydra

Please note that in order to complete all of these puzzles, you’ll need to have progressed the main story to the point that you have the first level of Alohamora unlocked.

Arithmancy Door Puzzle #1

Location: Rafters near Divination Classroom

Solution for left dial: Fwooper (4)

Solution for right dial: Runespoor (3)

Use the Divination Classroom Floo Flame, then turn around and head into the rafters, taking the first right. You’ll come upon an Arithmancy Door, with a note detailing the cipher needed to solve these puzzles to the door’s right.

Arithmancy Door Puzzle #2

Location: Arithmancy Classroom

Solution for left dial: Fwooper (4)

Solution for right dial: Quintaped (5)

After solving the first puzzle, go through the door to find the Arithmancy Classroom, which contains the second and third puzzles.

Arithmancy Door Puzzle #3

Location: Arithmancy Classroom

Solution for left dial: Salamander (6)

Solution for right dial: Unicorn (1)

Located in the same room as Puzzle 2.

Arithmancy Door Puzzle #4

Location: Troll room next to Library

Solution for left dial: Graphorn (2)

Solution for right dial: Unicorn (1)

Head to the Library Floo Flame, then go through the door next to it and down a short flight of stairs to a room with two trolls on display. The Arithmancy Door will be on your right.

Arithmancy Door Puzzle #5

Location: Hall across from Potions Classroom

Solution for left dial: Acromantula (8)

Solution for right dial: Runespoor (3)

After heading to the Potions Classroom Floo Flame, turn around and go back into the hall, where you’ll find this door directly in front of you.

Arithmancy Door Puzzle #6

Location: Great Hall

Solution for left dial: Acromantula (8)

Solution for right dial: Runespoor (3)

Head to the Great Hall. From the Floo Flame, turn around and take a left to find a small hallway with the Arithmancy Door.

Arithmancy Door Puzzle #7

Location: North Hall

Solution for left dial: Salamander (6)

Solution for right dial: Runespoor (3)

From the Transfiguration Classroom, turn around and take the doors on the left, then run up the stairs and go through a locked door. At the end of this cobweb-strewn hallway will be another puzzle.

Arithmancy Door Puzzle #8

Location: Outside Charms Classroom

Solution for left dial: Graphorn (2)

Solution for right dial: Grindylow (7)

From the Charms Classroom Floo Flame, simply turn around and go to the left corner to find this door.

Arithmancy Door Puzzle #9

Location: Ravenclaw Tower

Solution for left dial: Fwooper (4)

Solution for right dial: Quintaped (5)

At Ravenclaw Tower, you’ll find this door at the end of a hallway just before coming upon the spiral staircase.

Arithmancy Door Puzzle #10

Location: Grand Staircase Tower

Solution for left dial: Salamander (6)

Solution for right dial: Grindylow (7)

At the Grand Staircase Tower Floo Flame, just go down the stairs a short ways until you see this door.

Arithmancy Door Puzzle #11

Location: Lower Grand Staircase

Solution for left dial: Demiguise (0)

Solution for right dial: Quintaped (5)

From the Lower Grand Staircase Floo Flame, head towards the staircase then take a right to see the door.

Arithmancy Door Puzzle #12

Location: Prefect Tower

Solution for left dial: Demiguise (0)

Solution for right dial: Hydra (9)

Head up into the Prefect Tower to get this door. Note that you’ll need to be invisible in order to avoid being caught, so use Evanesco or an Invisibility Potion.