I use the calorie counter on Sparkpeople.com (a great diet/fitness site, btw) and it calculates my calories burned at 14-16 mph at 600 per hour. I'm pretty sure it's based on my age (46) and weight (134). Not terribly off the mark from your software (720?). The link Popoki-nui have shows it as 800 calories burned in one hour. My polar-type watch says something entirely different again. In fact, every website I visit has a different number of calories burned for similar cycling. I guess there really is no good way to calculate caloric burn.

On a related note, I was out riding for 3 hours today. Did mostly hills, some road, some off-road. All very challenging for me, heart rate up around 170 going up most hills, and stayed in range of 135-150 most of the time. I *KNOW* I burned a ton of calories today but I only averaged 14 kmh so the most of the charts will only show I burned about 600 calories over the 3 hours. Bull. I figure I burned at least 1200-1500 today. (Didn't eat anything along the way though

Barb