A1Z26 Cipher Decoder
Swap letters for their alphabet position (A=1, Z=26) or decode a number list back into words.
Keyboard: Ctrl or ⌘ + Enter copies. Escape clears. Text stays in this browser.
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A equals 1 through Z equals 26
Encoding maps each letter to its index in the English alphabet. Decoding reads numbers (often space- or hyphen-separated) back into letters. This is a classroom substitution, not encryption: there is no key, and frequency analysis is trivial.
Puzzles, worksheets, and what to use instead
Teachers use A1Z26 for intro cryptograms. Caesar and ROT13 add a shift; those are still toys. For secrets, use a real authenticated encryption tool—not this page, not MD5, and not Morse.
Punctuation, case, and non-English letters
Non-letters usually stay or become separators. Case is typically folded to A–Z. Accented letters are not in the 1–26 table unless stripped first. Encoding stays in the browser.
Frequently asked questions
Is A1Z26 used in real security?
No. It is a teaching cipher. Anyone who knows the mapping can read it.
How should numbers be separated?
Spaces or hyphens between letter values (8 5 12 12 15) decode more reliably than concatenated digits.
What about Ñ or other extra letters?
The classic puzzle uses 26 English letters. Extra letters need a custom alphabet this tool does not define.