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ToolWrenApply the Atbash substitution cipher, which mirrors the alphabet (A↔Z). The same action encodes and decodes.
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Atbash is a free, private online tool that lets you apply the Atbash cipher, mapping A to Z, B to Y and so on. It runs entirely in your browser, so nothing you enter is uploaded to a server.
Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.
Atbash reverses the alphabet: A becomes Z, B becomes Y, and so on. Originally used for the Hebrew alphabet.
Because the mapping is symmetric, applying Atbash twice returns the original text — one button does both.
Puzzles, ciphers in games and teaching substitution ciphers.
Atbash is an ancient substitution cipher that mirrors the alphabet: the first letter maps to the last, the second to the second-last, and so on - A becomes Z, B becomes Y, C becomes X. It originated as a cipher for the Hebrew alphabet (its name comes from the first, last, second and second-last Hebrew letters) and is one of the simplest ciphers in existence.
Each letter is replaced by its mirror image in the alphabet, found by the rule 'position from the start becomes the same position from the end'. Because the mapping is symmetric, Atbash is its own inverse - applying it twice returns the original text, so a single operation both encodes and decodes. Non-letters pass through unchanged.
Atbash has no key at all - the substitution is completely fixed - so anyone who knows it is Atbash can decode the message instantly, and even those who do not can crack it easily with frequency analysis. Like the Caesar cipher, it offers zero real security and is used today purely for puzzles, games and learning.
Atbash turns up in puzzle hunts, escape rooms, geocaching clues, and cryptography lessons as an accessible first example of letter substitution. It also has historical and literary interest - examples appear in ancient texts - making it a fun, simple cipher to know.
Type or paste your text and the Atbash-transformed result appears instantly; run it again on the output to get back the original. Only letters are changed - numbers and punctuation stay as they are. Everything runs in your browser.