Guide
A1Z26: turning letters into numbers and numbers into letters
A1Z26 is the simplest way to turn words into numbers: each letter becomes its position in the alphabet, so A is 1, B is 2 and Z is 26. “Hello” becomes 8-5-12-12-15. Children invent it on their own, puzzle hunts use it constantly, and it is a favourite lock code in escape rooms. This tool converts in both directions with the separators and variants you need.
Separators matter
Numbers need separators, because 1 and 1 next to each other could be AA or K. Choose a hyphen (8-5-12), a space, a comma or a dot between letters, and a space, slash, double space or vertical bar between words. When decoding, use the same choices as the person who made the code: with hyphens between letters, a single space separates words; with spaces between letters, words need a slash or a double space. If a code arrives without separators, it is genuinely ambiguous and must be split by trial, using the key table.
Variants
Some puzzles count from A = 0 (A is 0, Z is 25), which matches how computers number positions and how modular-arithmetic ciphers are explained. Others reverse the alphabet, so A is 26 and Z is 1, a sneaky combination of A1Z26 and Atbash. Switch these options on to encode or decode either form; the key table updates to show the numbering in use.
What happens to other characters
When encoding, letters become numbers, punctuation is kept between them, and digits already in the text are dropped so they cannot be mistaken for letters; write numbers as words first if they matter. When decoding, any number outside 1–26 becomes a question mark so mistakes are easy to see, and punctuation in the code is kept.
Ideas for games and lessons
Set a three- or four-digit lock code that spells a short word clue. Hide a message in a list of page numbers or prices. Use A1Z26 with young children to practise alphabet positions, or combine it with a Caesar shift for older students. The animated series Gravity Falls famously used A1Z26 for some of its end-credit puzzles.
Not secret
A1Z26 is instantly recognisable and has no key. It is for fun and teaching, not for keeping anything private.
Private
The conversion happens in your browser.
A worked example
To set a four-word clue for an escape-room padlock, type “Look under the rug” with hyphens between letters and slashes between words. The result is 12-15-15-11 / 21-14-4-5-18 / 20-8-5 / 18-21-7. Players who know A1Z26 decode it in a minute; to make it harder, switch on reversed numbering, which turns the same clue into 15-12-12-16 / 6-13-23-22-9 / 7-19-22 / 9-6-20. When decoding a code someone else made, try the normal numbering first: if the result is nonsense but every number is between 1 and 26, try reversed or A = 0 before assuming another cipher.
Related tools
Reverse the alphabet with the Atbash Cipher, shift it with the Caesar Cipher Solver, turn letters into grid coordinates with the Tap Code Translator, or into A/B groups with the Bacon Cipher.
Checked against the current version of the A1Z26 Cipher on .