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Atbash cipher

Mirror the alphabet so A becomes Z and Z becomes A — encoding and decoding in one step.

Input
Output
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Atbash cipher
Atbash is one of the oldest ciphers on record. It simply mirrors the alphabet: A becomes Z, B becomes Y, C becomes X, and so on down the line. Hebrew scribes used it more than two thousand years ago — the name itself spells out the swap, joining aleph–taw and beth–shin, the first and last letters of the Hebrew alphabet paired up. Paste any text and this tool applies the same mirror to the Latin alphabet, live as you type.
Only the twenty-six unaccented Latin letters are mirrored, and their case is preserved — HELLO becomes SVOOL and hello becomes svool. Everything else passes through untouched: accented letters such as č or ü, digits, punctuation, emoji and non-Latin scripts come out exactly as they went in. Because the mapping is perfectly symmetric, encoding and decoding are the same operation. Run ciphertext through the tool once more and the original text comes back, which is why there is no direction switch — one button does both jobs.
That symmetry makes Atbash a favourite for puzzle hunts, geocaching hints, escape rooms, CTF warm-ups and classroom introductions to cryptography. It is not a security measure: the cipher has exactly one fixed key, so anyone who recognises the pattern reads the message instantly. For a shifting variant try the ROT13 tool, and for text that genuinely needs protecting use password-based encryption.
Everything runs locally in your browser — nothing is uploaded and the page works offline. The tally under the output counts the mirrored letters, and you can copy the result, download it as a .txt file, or send it back to the input to flip it again.
FAQ
How do I decrypt an Atbash message?
Paste it and apply the cipher again. The mapping is its own inverse — mirroring twice restores every letter — so the same button encrypts and decrypts.
What happens to accented letters, digits and emoji?
They pass through unchanged. Only the 26 letters A–Z are mirrored, so "č", "ü", "9" and "🫐" come out exactly as they went in, and letter case is preserved.
Is the Atbash cipher secure?
No. It has a single fixed key, so anyone who spots the pattern can read the message immediately. Use it for puzzles and teaching, and password-based encryption for anything that matters.
Where does the name Atbash come from?
From the Hebrew letters it pairs: aleph with taw and beth with shin — the first and last, the second and second-to-last. Read together they spell "atbash".
Is my text uploaded anywhere?
No. The tool runs entirely in your browser and your text never leaves your device.