Calculating climb on a route

[mkidd]

I took the new (to me) bike for a short first spin around a loop I did a few times last year. I have not had a workout since Oct 2007. So out of shape, but I don't think I lost all of my base from last year.

This loop was fine today, easier than when I was using my mtn bike of course. It has a few pretty good hills and I went down to my granny gear since I'm so out of shape, but I was ok. It's not as hilly (or as long) as the Danskin Webster tri bike route that I managed to get through last year.

I use mapmyrun.com to figure out mileage and get an idea on speed b/c I don't have a computer, and it will also show you the elevation of your route. How do you figure out that you did a "+xx% grade climb"?
And what's considered a tough grade by normal standards and not just newbie out of shape standards?

The first one is a screen grab of today's route.

The second is a screen grab of Danskin Webster. Is it as hard as they say, or not really? Also, both were loops so why is there an asent and decent for Danskin, but not my local route? I'm sorry if I sound very stupid and I appreciate any insight!