I've poked around here and have read multiple forums that point out cardio machines over estimate how many calories you burn. So... I bought a HRM in hopes that it would give me th actual number of calories I burned. I ended up with a number higher than both the elliptical machine and the estimate from the calorie couning website I use.

Today I did 45 min on the elliptical - fat burning mode alternating between levels 6-7-8. Here are the Calories Burned numbers I got:

Elliptical Machine: 423
Calorieking.com: 477
Polar F6: 506

Which do I trust?

I went with Calorieking.com sice it's in the middle.
A couple of things to note: My elliptical does not ask you for your weight when you start. It's not the top of the line so I assume its ot measurig my weight when I step on. Should I assume since I weigh 222 I'm burning more than it's set to count for? Also - my heart rate on the F6 matched my heart rate on my elliptcal - so it seems accurate in that aspect.

Advice please?
Thanks!

I would trust your HRM that you are wearing because those websites only give you a general estimate, but the HRM is telling you what you are burning not what someone else might burn. I hope that helps.

I go by my Polar HRM - sometimes it is higher than the machines, sometimes lower. Mine does have 'own zone' setup where I can set the heart rates more customized to me. When I do that I get a little lower burned number - I usually run at a pretty high heart rate during exercise and standard formulas might give me a higher burn than is accurate because of that?

Use your HRM...I have the F6 too...when I'm doing running and incline intervals on the treadmill the HRM is always higher than the machine but if I'm doing just a "stroll" on the elliptical or treadmill it is much lower than the machine.

If you don't input your weight, then the elliptical is probably assuming a weight of around 150 lbs. So that might account for the difference between the calories it reports and your HRM.

The range is only about 75 calories between the three readings. Since you know that the elliptical machine is not calculating based on your weight then it makes sense that reading is lower. Does it really matter whether you burned 477 or 506 calories? I'd go with the reading on the HRM but just keep in mind that all of the readings are really just estimates based on your weight, heart rate, exertion level, etc.