Thursday, July 3, 2008

Percent Grade

Someone asked me how to compute the grade of a climb. Here's a quick and fairly accurate way. Divide the elevation gain ("rise") in feet by the length ("run") of the climb in miles. Then divide the result by 50 (52.8 = 1% of a mile). So 2500 feet of rise divided by 5 miles of run is 500. 500 divided by 50 is 10. So a 10% grade.

7 Comments:

At July 18, 2008 12:00 PM , Blogger thomas said...

that's interesting. are you sure that you divide feet by miles and not feet by feet or miles by miles?

 
At July 18, 2008 1:41 PM , Blogger Joe Friel said...

Well, you're actually dividing feet by feet since the 50 is just a quick way of getting at it instead of using 52.8 feet (1% of a mile).

 
At July 19, 2008 8:12 PM , Blogger thomas said...

got it and makes sense. work smarter and not harder!

 
At November 22, 2008 2:16 PM , Anonymous Anonymous said...

Can I figure out the average grade of a distance run? I ran 8.6 miles and climbed 5,016 feet.

 
At November 22, 2008 7:01 PM , Blogger Joe Friel said...

Divide 5016 b 8.6 and then divide the quotient by 50.

 
At November 23, 2008 10:35 AM , Anonymous Anonymous said...

Thank you! I appreciate your help.

 
At November 24, 2008 7:11 PM , Anonymous Ed said...

This is SO MUCH simpler than that metric nonsense. Imagine, dividing metres by metres? Madness!

 

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