KMKMom says:

Hi folks,

I received a new 405 as a Mother's Day gift. Prior to that, I was using my Nike+ for distance and my Polar HRM to estimate my calorie burn. I've used the 405 for a few runs and notice that the calories burned estimate seems to be quite low compared to what I was getting with my Polar for similar runs. Has anyone noticed this? I'm now wondering which is actually accurate.

 Mihai says:

Here is a comparison for my latest run:

Nike+: 844
Garmin 405: 879
MapMyRun website: 799

As you can see, in my case, the Garmin 405 is the most generous with the calorie "waste"
Overall, I am more than OK with the error margin.

 bendoke says:

make sure you have your weight the same in all the different web sites...also, even if you are off like by .08 miles...your calories will be different. Calories are calculated by weight and distance, but here is something else on the runners world website to throw into the mix...

The exact number of calories you will burn will vary depending on your age, sex and base metabolic rate, as well as the intensity at which you perform the exercise.

www.runnersworld.co.uk/news/article.asp?uan=3166

I think all in all...I wouldn't be too concerned whether you burn 800 or 880 calories...you'll burn that much the next hour of sitting in your chair...

 KMKMom says:

Actually for me, it's much more significant than 80 calories. It's more like a 150-200 calorie difference. Nike+ always gives me the highest burn, then the Polar and then the Garmin. I wonder if it has something to do with the max heart rate setting in the Garmin device.