>Let's say the font is Arial Normal 8 and FONTMETRIC(6), the average width, is 5 pixels. Leaving out TXTMETRIC() to make the example simple, let's say all of the characters in the string are "average".

I don't know the answer to what your asking, but I have a little trick to get the real length of a string in screen pixels. Add a label to a form, set its top to -100 and its Font and Size to whatever your measuring, and its caption to the string. Then Set its AutoSize to .T. and just read the length.