Is it right?

I go by the machine, because it knows the exact speed and intesity throughout your workout. It knows if you are at a 2 incline or a 10 and that you did 10min at 3 mph vs 20 min at 5 pmh.

Most other people will tell you to get a heart rate monitor, which I wish I had at this point too. If you can get one of those it would be the most accurate.

My HRM always shows more cals than the machine!!

I do not receive my HRM until sometime this week so I've been using the lowest amount between the actual machine and here just to be safe.

If it is another exercise like cycling or running, I use endomondo to track by gps my speed and distance and then use the lowest amount between here and endomondo.

Technically nothing can 100% accurately measure how much energy your body has burned during exercise.

The algorithms in gym equipment probably aren't that accurate but they make a guess based on your age, weight and the intensity of the workout. They'll use the energy consumption of the average person to come up with a number. If you're really fit you'll burn less energy than the read out because your body doesn't have to work as hard as the average person.

HRMs are probably the most accurate as they use your hear rate and how much the average person your age, height and weight would burn at that heart rate. It's closer to reality because even if two people's fitness levels are wildly different, if they both have the same heart rate then chances are their energy consumption is similar at that point in time.

Regardless, I just record the calories the machine reports. Calorie counting is about ball park numbers, not pin point accuracy. If you notice you're not losing weight then do more exercise or eat less. The numbers won't be spot on but you'll lose weight once you've fine tuned the diet/exercise balance.