easier with fonts such as courier new, where each character is the same width. Otherwise, the only thing I can think off the top of my head is to use a spare or hidden sheet, and with a macro, paste each line of text into a cell, then set the width of the column to auto fit selection, then check the width of the column. You can record a macro to do all of this except checking the width of the cell, which is just :
range("A1").width
If you need more help writing the macro, let me know. Some Excel guru is now going to tell you there is a much better way, but this is all I can think of. At least it gives you some numbers to play with!
PhilR