That would really depend on the size of the burger and the filling of the burger. Do remember that if the burger is loaded with a lot of things like lettuce, mushroom, the patty, mustard, mayo, ketchup, and tomatoes, all of them would add to the calorie count. So for the purpose of uniformity, let's use the typical McDonald's burger. A typical McDonald's burger would contain about 300 calories. If you upsize it, then you would probably get around 400+ calories.