The A1Z26 encoding or ("cipher") got its name from the way it works: A=1, B=2, ..., Z=26. It is simplest possible letters to numbers translation. Although the encoding is intended for the English alphabet, it can easily be used for other languages as well. This translation tool will help you easily convert letters to numbers using any alphabet.
Decode or encode A1Z26
Note that you can type in either the letters or numbers area.
The alphabet can be customized to any language.
A1Z26, or variants of letters to numbers, is frequently used in geocaching mystery caches (puzzle caches), CTFs and logic puzzles.