big difference in calorie burn

I ride my bike for 40 minutes at 10-12 mph. MFP says I burn 383 calories.
I put a little computer on my bike and it says I only burn 102 calories.
I'd say my computer is wrong.
Maybe it thinks I weigh 50 lbs instead of 211?
I'm sticking with MFP. I usually only eat 50 - 100 calories back if any and started at 243, so obviously it is working. I sure was shocked though when I saw the number yesterday.

Replies

  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Why do you think MFP is right? Because you want a bigger number, or do you have a reason?

    Speed isn't a very good way to judge effort on a bike. Wind, elevation, traffic, and other factors make a huge difference in both of these. I mean, riding 35 mph sounds really impressive, but not so much if it's down a hill, right?

    Anyway I'm pretty close to your weight and I can tell you it takes me about 220 kCals to do an afternoon ride around Lake Union, about 7.5 miles in 30 minutes. I'm measuring the energy with a power meter, not guessing at it.

    From experience I can say that MFP's cycling calorie estimates are 2x to 3x reality for me.
  • sijomial
    sijomial Posts: 19,809 Member
    Probably both wrong but you have given barely any information if you are asking for guidance/experience from others.
    102 is very low for 40 minutes even at that low speed.