Re: how to figure percent of slope or of grade

Chris,

Percent of grade probably goes back to the railroad engineering survey measuring chain is 100 feet long. [a land surveyor's chain is 66 feet long -- but that's a whole different discussion].

So, 1% is 1 in 100, 2% is 2 in 100, 2.5% is 2.5 in 100, etc.

divide the rise by the distance and convert the result to percent (move the decimal point two places to the right and add "%")

So, 2 in 100, 1 in 50 both come out to 2%. Same for 4 in 100 and 1 in 25 the result is 4%

To me it is easy, but that depends on what you're used to. (I worked for years with roadway, sewer, drainage plans, water plans and slopes of all of these are given as percent.)

Hope this helps all who may wonder about percent of grade

Brian

P.S. The 100 foot chain is related to the degree of curvature - and that is also a different discussion.