Letters to Numbers Converter
Letters become their position in the alphabet.
8-5-12-12-15 23-15-18-12-4
The letters to numbers converter replaces each letter with its position in the alphabet (A is 1, Z is 26) and reverses the process. This is the A1Z26 cipher, the simplest substitution there is, and it is used in puzzles, escape rooms and geocaching rather than for anything requiring secrecy.
How it works
Each letter maps to its ordinal position, case-insensitively. Non-letters pass through unchanged, which keeps punctuation and digits readable in the output.
- Letters within a word are joined by the separator you choose, hyphen, space or comma.
- Words are separated by two spaces, which is what makes the reverse direction unambiguous.
- Decoding splits on two-or-more spaces for word boundaries, then on single separators for letters.
The two-space word boundary is the only part of this that needs a convention. Without it, 8-5-12-12-15 23-15-18-12-4 and 8-5-12-12-15-23-15-18-12-4 are indistinguishable, and the second decodes as one nonsense word.
Examples
Encoding a phrase
Text
hello world
Separator
Hyphen
Result
8-5-12-12-15 23-15-18-12-4
H is the 8th letter, E the 5th, L the 12th. The two spaces between 15 and 23 mark the word boundary.
Decoding back
Numbers
8-5-12-12-15 23-15-18-12-4
Direction
Numbers to letters
Result
hello world
The round trip returns the original text in lowercase. Case is not preserved, because the cipher has no way to encode it.
Frequently asked questions
Is A1Z26 actually a cipher?
It is a substitution cipher, but not a secure one. There is no key, so anyone who recognises the scheme can read it immediately. It is used for puzzles, escape rooms and geocaching, where the point is a small obstacle rather than secrecy.
Why do words need two spaces between them?
Because without a word boundary the decoding is ambiguous. 8-5-12-12-15-23-15-18-12-4 could be one word or two, and there is no way to tell. Two spaces mark the break unambiguously while staying readable.
What happens to numbers and punctuation in the input?
They pass through unchanged. Only the 26 letters are converted, so a phrase like "meet at 5pm" keeps its 5 and its full stop, which usually makes the output more readable rather than less.
Is case preserved?
No. Both cases map to the same number, so decoding always returns lowercase. The cipher has no mechanism for case, and inventing one would break compatibility with every other A1Z26 implementation.