A medium egg white contains about 16 to 20 calories. The exact amount of calories in an egg white depends on the size of the egg and the cooking method.
A medium-sized egg, including the yolk, contains approximately 65 to 75 calories. Additional calories may be added if the egg is cooked in oil, butter or other forms of grease. Eggs contain healthy amounts of protein, most of which is found in the white of the egg. The yolk of an egg contains most of the fat and cholesterol content, but it also contains most of the fat-soluble vitamins, essential fatty acids and other nutrients found in an egg.