According to Self magazine, the calories in an egg depends upon its size. A large egg has 71 calories, while an extra large egg has 80 calories. Jumbo eggs contain 90 calories. Small eggs are typically 54 calories each, and medium-sized eggs contain 63 calories.
The calorie count of eggs also varies depending upon how they are prepared. For instance, adding butter, sauce or cheese significantly increases the number of calories.
Eggs are highly nutritious. A single large egg has 6 grams of protein and a substantial amount of selenium, phosphorus, vitamin B12 and riboflavin. Although it has 5 grams of fat, this includes heart-healthy omega fatty acids. An egg's cholesterol count is relatively high, however, at 211 milligrams. Most of the cholesterol found in eggs is in the yolk.