Atbash Cipher
Swap every letter with its mirror in the alphabet (A↔Z, B↔Y, C↔X) to encode or decode Atbash text instantly, in English or in the original Hebrew. It works right in your browser, and the same button encodes and decodes.
Latin letter mapping
Each letter swaps with its mirror: position n becomes 27 − n. Letters used in your text are highlighted.
Hebrew letter mapping
How to use the Atbash Cipher
- Type or paste your text or Atbash ciphertext into the left box.
- Read the result on the right: it updates as you type. Press Encode / decode to confirm.
- Pick alphabets: Latin A–Z, Hebrew, or digits 0↔9, and an output format.
- Check the mapping table to see which letters were swapped.
- Copy the result, or press Use result as input to reverse it.
Atbash alphabet table
| Plain | A | B | C | D | E | F | G | H | I | J | K | L | M |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cipher | Z | Y | X | W | V | U | T | S | R | Q | P | O | N |
| Plain | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
| Cipher | M | L | K | J | I | H | G | F | E | D | C | B | A |
Because the table is symmetric (A↔Z is the same pair as Z↔A), encryption and decryption are identical. The formula with A = 0 … Z = 25 is C = 25 − P, which is also the affine cipher E(x) = (25x + 25) mod 26.
Worked examples
| Plaintext | Atbash | Note |
|---|---|---|
| HELLO WORLD | SVOOL DLIOW | Classic test phrase |
| WIZARD | DRAZIW | Reads as a reversed word: a well-known Atbash curiosity |
| HOLD | SLOW | An English word pair that maps onto another word |
| בבל (Babel) | ששך (Sheshach) | Jeremiah 25:26 and 51:41 |
How to recognise and break Atbash
Atbash has no key, so if you suspect it, just apply it once. Signs that a puzzle uses Atbash include many V, Z and R letters (the mirrors of E, A and I), and short words like GSV (THE) and ZMW (AND). If Atbash does not give readable text, try a shift cipher with the Caesar Cipher tool, or the keyword-based Vigenère Cipher.
Atbash, A1Z26 and other simple codes
Puzzle makers often combine Atbash with other easy codes. In A1Z26 each letter is replaced by its number (A = 1 … Z = 26); applying Atbash first and then A1Z26 turns every number n into 27 − n, so 8-5-12-12-15 (HELLO) becomes 19-22-15-15-12. A reversed Atbash message (written backwards as well as mirrored) is another classic twist. Because Atbash only has one possible mapping, a quick test is always worth it before you try frequency analysis or shift ciphers.
Frequently asked questions
How does the Atbash cipher work?
Atbash replaces each letter with the letter at the same position from the other end of the alphabet: A becomes Z, B becomes Y, C becomes X and so on. In numbers, letter n (A = 1) becomes letter 27 − n. HELLO becomes SVOOL.
How do I decode Atbash?
Exactly the same way you encode it. Atbash is its own inverse, so applying it to SVOOL gives HELLO again. Paste the ciphertext and the result is the plaintext.
Where does the name Atbash come from?
It comes from Hebrew: the first letter aleph (א) swaps with the last letter tav (ת), and the second letter bet (ב) swaps with the second-to-last shin (ש), giving א-ת-ב-ש, Atbash. It appears in the Book of Jeremiah, where Sheshach (ששך) stands for Babel (בבל).
Is Atbash a Caesar cipher?
No. A Caesar cipher shifts the alphabet, while Atbash reverses it. Both are monoalphabetic substitution ciphers with only one possible key, so they offer no real security and are easy to solve by hand.
What happens to Hebrew final letters?
Final forms (ך ם ן ף ץ) are treated as their regular letters before swapping. With Hebrew final forms at word end on, a kaf, mem, nun, pe or tsadi that ends up at the end of a word is written in its final form, as in ששך.
Where is Atbash used today?
In puzzle hunts, escape rooms, geocaching, school cryptography lessons and TV puzzles such as the cryptograms at the end of Gravity Falls episodes, which use Atbash, Caesar and A1Z26 codes.