Character count starts from 1 in both Kate and KWrite, this means that when 5 characters are typed the indicator marks 6. This is quite confusing and different from all other text editors. Character count should start from 0, so it displays 5 after 5 characters are typed.
If you are referring to the 1:x thing, then it is linenumber:column number, and not a character count. The colume number starts from 1 instead of 0 because what you type will be inserted into the first colume.