How to Reach Room 46
The Vault is one of the three conditions. See the full route to the final door.
Read the routeBlue Prince Vault Code — 4558
The Vault code in Blue Prince is 4558. The code is fixed in every run and every save file — there is no per-run randomization. This guide explains where the three hint letters are, how the code is encoded, and why it has to be 4558.
The Vault code is
4558. Enter on the Vault dial in the East Wing. Costs 1 Key to open the steel door first.
Code Derivation at a Glance
The Three Letters
Each of the three letters has exactly one word underlined or italicized. The first letter of that word is your hint.
| Location | Where Exactly | Underlined Word | First Letter |
|---|---|---|---|
| Den | Top-right desk drawer | Door | D |
| Library | Second shelf, "On the Architecture of Memory" | Open | O |
| Office | Corkboard above writing desk | Outside | O |
| (Implied) | The fourth letter completes DOOR | Return | R |
The fourth letter trick: Many players miss that there's a fourth implied word. The three letters spell DOO — the R comes from the last word of the third letter, which references "return" or a similar R-word. Read each letter to its end.
How to Decode (Step by Step)
- Collect all four underlined words. Across the three letters in Den, Library, Office, the underlined words spell DOOR.
- Convert each letter to its alphabet position. A=1, B=2, ..., Z=26. So D=4, O=15, O=15, R=18.
- Apply mod 10 to each number. 4 mod 10 = 4. 15 mod 10 = 5. 15 mod 10 = 5. 18 mod 10 = 8.
- The Vault code is 4-5-5-8. Enter it on the Vault dial. The steel door swings open after one Key is used.
What's Inside the Vault
The Vault is in the East Wing. Once opened, it contains:
- The deed paper — picking it up satisfies the first of the three Room 46 conditions. This is the main reason to open the Vault.
- 2–3 Keys — useful late-game to push through steel doors.
- ~15 Gems — a flat reward, not multiplied by anything.
- One Marksman's Pin (sometimes) — only on first-ever Vault open across runs. See the Dartboard guide.
Vault Code FAQ
What is the Blue Prince Vault code?
The Vault code is 4558. It's fixed across every run and every save file in the current version.
Why is the Vault code 4558?
It's derived from the word DOOR. D=4, O=15, O=15, R=18. Each digit mod 10 gives 4-5-5-8.
Where are the three Vault code letters?
Den (top-right desk drawer), Library (bookmarked page in "On the Architecture of Memory"), Office (corkboard above the writing desk).
Is the Vault code different in my run?
No. The code 4558 is fixed. Only the room layout changes between runs.
What's inside the Vault?
The deed paper (Room 46 condition), 2–3 Keys, ~15 Gems, and on first-ever open, the Marksman's Pin.
Related Guides
All Major Puzzles
Boiler Room, Billiard Room, Constellation, Dartboard, Parlor — every solution.
All solutionsDay 1 Strategy
The Vault letters are best collected on day 1 — here's the optimal recon route.
Plan day 1Items List
Brass Key, Marksman's Pin, Telescope Lens — every item and where to find it.
Item index