Atbash / Reversed alphabet

Atbash cipher

Transform text with the self-inverse Atbash cipher. This variant mirrors only the 26 ASCII Latin letters A-Z and a-z while preserving case and every other character.

01 / Workspace

Mirror the alphabet

ASCII A-Z / a-z
0 / 5,000 code points

Uppercase stays uppercase and lowercase stays lowercase. Accents, non-Latin scripts, emoji, digits, whitespace, and punctuation pass through unchanged. Press Ctrl+Enter or Command+Enter to transform.

Ready to transform.

02 / Result

Transformed text

No result yet
0 code points

Atbash is self-inverse. Paste this result into the input and select Transform again to recover the original text.

03 / Guide

How this Atbash variant works

The historical Atbash idea reverses an alphabet. Here, each ASCII letter at zero-based position x maps to position 25 - x. Uppercase and lowercase are mirrored separately, so A maps to Z, B maps to Y, and m maps to n. Applying the same mapping twice returns every letter to its starting position.

InputABCDEFGHIJKLMNOPQRSTUVWXYZ
OutputZYXWVUTSRQPONMLKJIHGFEDCBA

Known checks

Mixed case
Hello, World! maps to Svool, Dliow!.
Full alphabet
ABCDEFGHIJKLMNOPQRSTUVWXYZ maps to ZYXWVUTSRQPONMLKJIHGFEDCBA.
Round trip
Cifraex 2026 😀 maps to Xruizvc 2026 😀, then back to Cifraex 2026 😀.

Preservation, limits, and security

  • This tool transforms only ASCII letters with code points U+0041 through U+005A and U+0061 through U+007A. It does not transliterate or normalize Unicode text.
  • All other Unicode code points are copied unchanged. Combining marks remain separate, and emoji sequences keep their original code points.
  • Browser text controls normalize CR and CRLF line endings to LF. After that browser normalization, line breaks are preserved by the transform.
  • Input is limited to 5,000 Unicode code points so repeated actions remain responsive. Text over the limit stays in the input until you shorten or clear it.
  • Classical ciphers are educational and unsuitable for protecting sensitive data. Atbash has no secret key and is trivial to reverse.