I have started using MapMyRide.com to keep track of my bike rides as a motivational tool to keep riding and improve my health and fitness.

However, when comparing the calorie counter from various sources on the 'net with the one used on MapMyRide, the MMR one is about 15-20% lower.

Anyone else discovered the same?

On the other hand, perhaps I could ask myself, should I even bother thinking about it?