one "simple" way to distill it is like this...

this assumes:

1. flat surface
2. standard high-level road bike equipment
3. no head/tail wind

I also naïvely assume that I ride a total of 0m elevation change on a round-trip commute ... so I average my ride to be flat for the day, which makes the chart easier for me to use:



for me, I average 30km/h on my short commute to work (if one believes my cycloputer), which is in between the 15mph and 20mph lines and I weigh roughly 80kg (damn cheap English beer) ... and my RT commute takes 40 mins rolling (20km) ...

so, I end up with about 12kcal/min or about 480 total for the RT commute.

does that seem about right to you guys? 480kcal for 40mins with an 80kg weight at an average of 30km/h (18,75mph)?