As everyone knows -to stay lean (or loose weight) people should burn at least the same amount of calories they got from the food. This is very simple calories burner calculator -just input height/weight and chose activity from menu. Calculation is based on average data for such activities (average age and average build). There is an option that allows to chose gender (Male/Female). Have to notice that activity named "exercise" (both "normal" or "intensive") is a general name (same amount of burned calories) for any kind of sporting activity such as working out in a gym, riding a bike and, according to some researches, even having sex.