Calories that you have utilized while doing a physical activity can be calculated in two ways i.e. either by using the heart rate during the workout or by calculating the type of physical activity performed and for what passage of time.
If you are not aware of your heart rate then you can calculate the calories you have managed to burn by just inputting the the type of work out performed and for what period of time. For example a 20 minutes of cycling will burn only 100 calories. Is'not it interesting.?
The calorie burn calculator can amaze you by showing how much calories you have burnt.