Elliptical training and burnt calories - what numbers can I trust the most?

[PeterWesterlund]

I have got an elliptical machine and wanna track my workouts and somehow compare it to when I have been running. Since elliptical workout isn't running, more close to bicycling when it comes to how much effort it takes to get to a certain "distance", I have to try to think a good way to compare.

And I have realised that what I wanna achieve is to burn as many calories as I did when I was running let say 2 km outside. So I looked back on an old Runkeeper tracking I had saved and it said that I burnt 100 calories in 2 km. So, I tried to first just go by my elliptical machine's own tracking to see what 100 calories meant in elliptical distance and effort. And I couldn't even get there. I almost past out. And this was on level 5 on the machine.

Then I tried with my fitbit, on elliptical tracking setting, and when I got to 100 calories on my fitbit, the machine was on around 50 calories burnt.

How can it be such a difference? Which is more accurate? And why? I feel like my elliptical machine should be more accurate since it knows exactly how many and how long steps I taken, it also knows my weight and it knows what level I'm running on. But the fitbit is much closer to the effort made when I was running outside and was tracking with my iphone and runkeeper. Maybe it was wrong at that time? Maybe 50 calories burnt on 2 km is what I bruned even with my iphone and runkeeper?

Can anyone help me make this more clear?

[AlvaroFitbit]

@PeterWesterlund It's nice to have you on board! Sorry for the delay in my reply.

Let me help you with your caloric burn difference between your tracker and your elliptical machine. Your tracker will use your personal information (age, weight, height, etc.) and your movement+heart rate to calculate the calories you burn during an activity. Not sure if your elliptical machine will include the BMR calories (the ones based on your information). Since these are two different devices you could reach out to your health professional to see which ones reflects more accurately what your own body (it is different to everyone) burns for these activities. You could also check online calorie calculators to see what is the general consensus.

Let me know how it goes.