Calories burned while working out

When I do a treadmill program, the calories are fairly close to sp--usually a bit up, because I do intervals and sp doesn't count for that.

HOWEVER, sp gives me an insane amount of calories burned for doing the elliptical...my elliptical doesn't allow me to put in for weight but the number is WAY (think less than 20%) lower than sp estimates. I figure it's in between...I'm bigger so burn more calories than most, but I'm slow so I burn less than most as well...

Yep they do ask my weight/age. Not my lifestyle though like spark asked when I signed up. The bodybugg is in my list of future purchases with my taxes.

do the machines at the gym ask your weight? i know that the ones i get on dont, nor does my gazelle. it just gives a cal burn that would be the same for anyone getting on. I also have a bodybugg..it figures cals by your bodyweight and the amount of effort it detects. it matches pretty closely with spark...

So when I am working out I am always sure to get on cardio equipment that does track my heart rate and calories.

The calories shown there are always quite a bit lower than was SP gives me credit for when I log my cardio work. Is that because SP knows more about me and my body than the machine does at the gym ? Or is this an accepted variance ?

I guess my main concern is that I want to be sure that I am getting the cardio work I need. At least I do have my work to fall back on with help on that too. Last night was incredibly aerobic !