I have a Polar 200 cadence heart rate/cyclometer. I'm 37, 5' 7" 138lbs. In the Northern California region there was a challenge put out of how much you could climb in an hour starting from home. In 58 minutes (not including a couple red lights) I got to the top of the steep section of a local 8 mile climb, Page Mill road. The grade is fairly inconsistent as it goes from 7% or 8% to over 15%. When I stopped and checked, the Polar indicated 640 calories. Most of my work day rides are 1.5 to 2 hours, 23-28 miles in length. A light day will be 950-1000 calories and a heavy hill repeat will be 1200-1300. No clue on how accurate this all is but it's a good indicator if I can justify that apple fritter at Starbucks or not.