Converter Tools

Atbash Cipher

Encode and decode Atbash cipher text in your browser. Latin A-Z and original Hebrew Aleph-Tav alphabets, case preservation, and a live mapping table.

Settings

Atbash is its own inverse, so encoding and decoding run the same mapping. The toggle just clarifies your intent and labels the panes.

Direction

Alphabet

Each letter mirrors to its alphabet partner: A <-> Z, B <-> Y, M <-> N.

Output case

Non-letters (digits, spaces, punctuation)

Atbash only transforms letters. Keep passes spaces and punctuation through; Drop removes everything that is not a letter.

Plain text0 chars

Atbash cipher text

Output appears here as you type.

Letters mapped

Other chars kept

Chars dropped

Latin Atbash reference

Each letter pairs with its mirror across the alphabet. The mapping is symmetric.

A↓Z

B↓Y

C↓X

D↓W

E↓V

F↓U

G↓T

H↓S

I↓R

J↓Q

K↓P

L↓O

M↓N

N↓M

O↓L

P↓K

Q↓J

R↓I

S↓H

T↓G

U↓F

V↓E

W↓D

X↓C

Y↓B

Z↓A

What is the Atbash cipher?

Atbash is one of the oldest known substitution ciphers and predates both the Caesar and Vigenere ciphers. It originally applied to the Hebrew alphabet, swapping Aleph (the first letter) with Tav (the last), Bet with Shin, and continuing inward until each letter has been paired with its mirror. The name comes directly from those first two pairs: Aleph-Tav-Bet-Shin, which Hebrew readers contract to AT-BaSh. The exact same idea applied to the 26-letter Latin alphabet pairs A with Z, B with Y, all the way to M with N, which sit at the middle. Because the mapping is symmetric, encoding a piece of text twice with Atbash returns the original plaintext, which makes the cipher easy to verify and impossible to get wrong on the direction.

Where Atbash shows up

Hebrew scriptures contain a few notable Atbash substitutions, most famously the word Sheshach in the Book of Jeremiah, which decodes to Babel.
Capture-the-flag and escape-room puzzles use Atbash because the cipher is recognisable by hand once you spot a mirror pattern in the output.
Cryptography courses use Atbash as a teaching example for monoalphabetic substitution and as a stepping stone to the more general Caesar shift.
Atbash is not safe for real-world security: the mapping is fixed, so any letter-frequency analysis breaks it immediately.

How to use

Pick a direction. Atbash is its own inverse, so Encode and Decode run the same mapping; the toggle just labels the panes for clarity.
Choose an alphabet. Latin (A-Z) covers English-language text; Hebrew (Aleph-Tav) covers the original biblical cipher and renders right-to-left.
Set Preserve case (or force UPPERCASE or lowercase) for Latin output, and decide whether digits, spaces, and punctuation should pass through or be dropped.
Paste your text into the left panel. The right panel updates instantly with the Atbash-mapped result and a count of letters mapped, characters kept, and characters dropped.
Click Copy to grab the output, Use as input to feed the result back in for a round-trip check, or Load sample to see a typical plaintext or ciphertext example.

About this tool

Atbash Cipher is a classical monoalphabetic substitution cipher that swaps each letter of an alphabet with its mirror image, so the first letter pairs with the last, the second pairs with the second-to-last, and so on toward the middle. On the 26-letter Latin alphabet that means A pairs with Z, B with Y, C with X, all the way to M paired with N at the centre. On the original 22-letter Hebrew alphabet the same idea pairs Aleph with Tav and Bet with Shin, which is where the name comes from: AT-BaSh. Because the substitution is symmetric, running text through Atbash twice returns the original plaintext, which makes encoding and decoding the exact same operation. This tool runs both directions, supports either the Latin (A-Z) or Hebrew (Aleph-Tav) alphabet, preserves or normalises case on demand, and lets you choose whether to keep digits, spaces, and punctuation verbatim or strip everything that is not a letter. Hebrew final-form letters (Kaf-sofit, Mem-sofit, Nun-sofit, Pe-sofit, and Tsadi-sofit) are mapped to the same Atbash partner as their non-final equivalents so the substitution lands on the canonical letter regardless of position. A live mapping table shows every letter and its Atbash partner so you can verify the substitution by hand, and quick-load buttons offer ready samples in both alphabets. The encoder runs entirely in your browser; the text you paste never leaves your device. Atbash is the oldest known substitution cipher, appears in passages of the Hebrew Bible (most famously the word Sheshach in Jeremiah, which decodes to Babel), and remains a staple of capture-the-flag puzzles, escape rooms, and cryptography 101 courses. It is not safe for real-world security: the mapping is fixed, so letter-frequency analysis breaks it instantly. Use this tool to solve a puzzle, decode a clue, teach a class, or check a CTF challenge submission.

Free to use. Works in your browser. No signup, no login.

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Atbash Cipher

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