A1Z26 Cipher
8-5-12-12-15 23-15-18-12-4
Encode letters into their alphabet positions
Every letter maps to its 1–26 index (A = 1 … Z = 26). Numbers in a word are joined with hyphens, e.g. “Hello World” becomes “8-5-12-12-15 23-15-18-12-4”. Digits, punctuation, and other non-letters are dropped and simply break one word from the next.
When to use this tool
Reach for the A1Z26 cipher when a puzzle, CTF challenge, escape room, geocache, or classroom crypto lesson hides a message as numbers — each letter swapped for its position in the alphabet (A = 1 … Z = 26). It rounds out the classical ciphers here (Caesar, Vigenère, Atbash, Rail Fence, Bacon): instead of turning letters into other letters, it maps every A–Z letter to its ordinal number, and reading those numbers back recovers the message.
Privacy and limitations
Everything runs locally in your browser; nothing is sent anywhere. This is a classical cipher, not real encryption — the fixed letter-to-number table is trivial to reverse. Encoding is case-insensitive and drops any non-letter, treating runs of them as word breaks. Decoding returns letters in uppercase and only restores the letters, so the original case, spacing, and punctuation are not recovered. Number tokens outside 1–26, or anything that isn't a number, are reported as invalid input.