This doesn t explain much After reading the article I still found myself wondering how grades are calculated The table would suggest a 9 grade is merely 5 but I was on a 9 road today and it must have been at least 30 The linked page offers a much clearer answer that the grade is simply 100 rise run Perhaps this is not a common standard but it is certainly used in Northern Alberta and BC Though I still don t understand why percentages are used at all