Arc Trainer Calorie Calculator How Accurate Are The Calorie Counters On Cardio Machines?

How accurate are the calorie counters on cardio machines? - arc trainer calorie calculator

I am almost certain that these counters are the estimated calories burned. How do I measure my rate of calorie burn when I made at these counters? For example, the coach told me that using the bow, the burned 400 calories in 35 minutes. This may not be correct. Comments?