Atbash Cipher Encoder & Decoder

Encode or decode Atbash, the cipher that reverses the alphabet (A↔Z, B↔Y). One box works both ways, keeps your punctuation and shows the full key.

Atbash replaces each letter with its mirror in the alphabet: A becomes Z, B becomes Y, C becomes X and so on, so HELLO becomes SVOOL. Because the swap is symmetrical, encoding and decoding are the same operation: run SVOOL through again and you get HELLO back. Atbash began as a cipher for the Hebrew alphabet, and its name comes from the Hebrew letters aleph, tav, bet and shin. It has no key, so it offers no security, but it's a common first cipher in escape rooms, puzzle books and classroom code-breaking because players can solve it with the alphabet written forwards above the alphabet written backwards. The tool keeps case, digits and punctuation exactly as typed.

Text to encode or decode

Atbash is its own inverse: the same step encodes and decodes.

Output format

Keep upper and lower case

Atbash result

Svool, Dliow!

Atbash key

Each letter swaps with the one in the same column: A↔Z, B↔Y, C↔X and so on.

ABCDEFGHIJKLMNOPQRSTUVWXYZZYXWVUTSRQPONMLKJIHGFEDCBA

Common use cases

Decode an Atbash clue in an escape room or puzzle book
Make a beginner cipher that needs no key, only the alphabet backwards
Print the Atbash key as a handout for players or students
Check whether a mystery message is Atbash before trying other ciphers

How to use

Type or paste your text into the box.
The Atbash version appears instantly. The same step encodes and decodes.
Use the key table to see every letter pair, or copy the result.

FAQ

Is Atbash the same as ROT13?

No. ROT13 moves every letter 13 places along (A becomes N), while Atbash mirrors the alphabet (A becomes Z). Both are their own inverse, but they only agree on two letters: G and T, which swap with each other in both.

Does Atbash have a key?

No. The substitution is always the same, so anyone who knows the method can read the message. That makes it a puzzle step, not encryption.

Where does the name Atbash come from?

From the first, last, second and second-to-last letters of the Hebrew alphabet: aleph, tav, bet and shin. The cipher swaps aleph with tav, bet with shin and so on, and the same idea applied to the Latin alphabet gives A↔Z, B↔Y.