Number to Letter Converter

About the Number to Letter Converter

Our free number-to-letter converter does the reverse of the A1Z26 cipher, turning a list of numbers back into the letters they represent, so 1 becomes A, 2 becomes B, and 26 becomes Z. Enter numbers separated by spaces, commas, or dashes and the tool decodes them into readable text in an instant. It is the perfect companion for solving puzzles, decoding messages a friend has encoded, running classroom cipher exercises, working through escape-room clues, and checking geocaching coordinates. Because it accepts several common separators, you can paste numbers in whatever format you already have without reformatting them first. Everything happens locally in your browser as you type, so results are immediate, no account is required, and your numbers are never uploaded anywhere.

Features

Auto-detect space, comma or hyphen separators
Choose A=1 or A=0 mapping
Uppercase or lowercase output
Out-of-range numbers use ?
Live browser-only conversion

How to use this tool

The Number to Letter Converter works right in your browser — no signup, no installation. Follow these steps:

Type or paste your number sequence (e.g. "8 5 12 12 15").
Select the separator matching your inputs (Space, Comma, Dash, or None).
Choose a casing preference (UPPERCASE or lowercase).
Copy the compiled text output.

Frequently asked questions

What is the A1Z26 cipher?

It is a simple substitution cipher where each letter of the alphabet is replaced by its corresponding number index (A=1, B=2, etc.).

What happens to negative numbers or numbers above 26?

Numbers out of bounds are ignored or marked with a placeholder depending on your settings.

Using the results

Use the Number to Letter Converter to transform supported text or data formats in your browser. Review the output before replacing your original, since some conversions change formatting or discard information.

Conversion Settings