According to the USDA, the average weight of a medium-sized orange is 131 grams, while a larger orange weighs approximately 184 grams and a smaller one around 96 grams. A medium-sized orange contains approximately 62 calories, while larger and smaller ones contain around 86 and 45 calories, respectively.
Oranges are a rich source of many vitamins and minerals, the most plentiful nutrient being Vitamin C, which plays a critical role in normal growth and development. It also helps to repair tissues in the body, and the antioxidant properties of Vitamin C work to combat free radicals and prevent some of the damage caused by them. Oranges also contain other essential nutrients, including fiber, Vitamin B1, copper, folate, potassium, pantothenic acid and calcium. Vitamin C is essential to a person's diet because the body does not produce it on its own.