How to convert letters to numbers
Type or paste text and the numbers appear below. The Upload icon loads a text file.
- Choose Letters → Numbers to encode, or Numbers → Letters to decode.
- Pick a numbering: A1Z26, A0Z25 or Reverse.
- Pick the separator that goes between the numbers of one word. Spaces in your text always mark word boundaries.
- Check the breakdown under the result to see which letter became which number.
Numbering schemes
A1Z26 is the common one: A is 1 and Z is 26, so "HI" is 8-9. A0Z25 starts at zero, as programmers count, so "HI" is 7-8. Reverse counts from the other end, with A as 26 and Z as 1, so "HI" is 19-18.
Only the 26 Latin letters are converted. Digits, punctuation and accented letters stay where they are.
Decoding numbers
Decoding splits each word on the separator and turns every number in range into a letter. Numbers outside the range, such as 27 in A1Z26, and anything that is not a number are passed through unchanged.
Decoded text is always upper case, since a number carries no case. If the separator does not match your data, a token such as 89 is read as one number and left as it is.
Frequently asked questions
What is A1Z26?
A1Z26 is a simple cipher in which each letter is replaced by its position in the alphabet, so A is 1, B is 2 and Z is 26.
Why is decoded text always upper case?
A number carries no case information, so decoded letters are written in upper case. Spaces and other characters from the numbers text are kept.
What happens to numbers outside the range?
They are passed through unchanged. In A1Z26 that means 0 and anything above 26, and in A0Z25 anything above 25.
Are word breaks kept?
Yes. Spaces and line breaks in the text mark word boundaries and are kept in both directions. The separator only goes between the letters of a single word.
Is my text uploaded?
No. The conversion runs in your browser and the text is not sent anywhere.