Atbash Cipher
Mirror the alphabet so A swaps with Z, B with Y, and so on. Atbash is its own inverse, so one field both encodes and decodes as you type.
Mirrored live as you type. Everything runs in your browser and nothing is uploaded.
Each letter keeps its original case. Digits pass through unchanged.
| Plain | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cipher | Z | Y | X | W | V | U | T | S | R | Q | P | O | N | M | L | K | J | I | H | G | F | E | D | C | B | A |
How to encode or decode Atbash cipher online
Paste your text
Type or paste the text you want to transform into the input box; it runs live with no button to press.
Read the mirrored result
Each letter is swapped for its mirror in the alphabet, and because Atbash undoes itself the same field encodes and decodes.
Adjust the options
Keep case as it is or fold the result to uppercase, and optionally mirror digits so 0 swaps with 9.
Copy the result
Copy the transformed text with one click; spaces, punctuation, and symbols keep their exact positions.
Why use this tool
Encode and decode in one field
Atbash is its own inverse, so applying it twice returns the original. Paste scrambled text to read it or plain text to scramble it, with no mode to switch.
Reverses the whole alphabet
A swaps with Z, B with Y, and M with N in the middle, all the way across. By default uppercase mirrors to uppercase and lowercase to lowercase.
Optional uppercase and digit mirroring
Turn off preserve case to print the result in uppercase like a classic cipher, and switch on digit mirroring so 0 to 9 flips to 9 to 0.
Letters only, everything else untouched
Only A to Z and a to z change. Spaces, punctuation, line breaks, accented letters, and emoji pass through in place, so structure is preserved.
Cipher alphabet reference
A compact plain-to-cipher alphabet chart sits under the output so you can trace any single letter to its mirror by hand.
Runs entirely in your browser
Everything happens on your device; nothing is uploaded.
About this tool
Atbash is one of the oldest substitution ciphers, first used to encode Hebrew script and now applied just as easily to the Latin alphabet. It works by reversing the alphabet: A swaps with Z, B swaps with Y, and so on down to M and N in the middle. Because the mapping is a straight mirror, running Atbash a second time returns the original text, which is why a single field both encodes and decodes. This tool applies that mirror live as you type. Only the letters A to Z and a to z are transformed; spaces, punctuation, line breaks, accented letters, and emoji stay exactly where they are.
By default each letter keeps its original case, so uppercase mirrors to uppercase and lowercase to lowercase. Turn off preserve case to write the result in uppercase the way classic ciphers are usually printed. You can also mirror digits so 0 swaps with 9, 1 with 8, and so on, which some puzzle variants use. Atbash is obfuscation rather than encryption and offers no real security, so use it for spoilers, puzzles, answer keys, and light scrambling, not for protecting sensitive data. Everything is computed on your device, so whatever you paste never leaves the page. For other reversible ciphers, try ROT13 to rotate letters by thirteen, the Caesar cipher to shift by any amount, or the Vigenère cipher for a keyword-based substitution.
Frequently asked questions
- What is the Atbash cipher?
- Atbash is a substitution cipher that maps each letter to its mirror in the alphabet: A to Z, B to Y, C to X, and so on. It is one of the earliest known ciphers and, because the alphabet is simply reversed, encoding and decoding are the same step.
- How do I decode Atbash?
- Paste the scrambled text into the same box. Atbash is its own inverse, so applying it again reveals the original message. There is no separate decode mode to choose.
- Does it change numbers, punctuation, or emoji?
- Only the letters A to Z and a to z are mirrored by default. Spaces, punctuation, line breaks, accented characters, and emoji pass through unchanged. You can optionally turn on digit mirroring to also flip 0 through 9.
- Is the Atbash cipher secure?
- No. Atbash is obfuscation, not encryption, and the fixed alphabet mapping is trivial to reverse. Use it for spoilers, puzzles, and light scrambling, never to protect passwords or private data.
- Is there a limit on how much text I can convert?
- There is no fixed limit. The tool mirrors text live as you type, and even large pasted documents are processed on your device in a single pass.
- Is my text uploaded anywhere?
- No. Everything runs in your browser; nothing is sent to a server.
Related tools
ROT13 Encoder
Apply the classic ROT13 cipher or any ROT-N shift from 1 to 25. Letters rotate, everything else stays put, and you get the encoded and decoded text at once.
Caesar Cipher
Encode and decode Caesar cipher text with any shift, then brute force all 25 keys to crack it.
Vigenere Cipher
Encode and decode Vigenere cipher text with a keyword, preserving case and punctuation, and watch the running key line up with each letter.
API Key Generator
Generate cryptographically random API keys and tokens in hex, base62, or base64url, with control over length, an optional prefix, and bulk output.
ASCII Table Reference
The full ASCII character set with decimal, hex, octal, binary, and HTML codes. Search by code, character, or name.
Base32 Encoder and Decoder
Encode text to standard Base32 and decode Base32 back to text, following RFC 4648.