The number of calories in eggs varies depending on their size:

• Small egg: about 54-55 calories
• Medium egg: about 63-66 calories
• Large egg: about 72-80 calories
• Extra-large egg: about 80-90 calories
• Jumbo egg: about 90-131 calories

On average, a medium egg contains around 66 calories. Most of these calories come from the yolk, which is richer in nutrients. The method of preparation can also affect the calorie count; for example, scrambled eggs with milk and butter have more calories than boiled or poached eggs without added fat. For 100 grams of whole fresh egg, there are approximately 143-155 calories. Thus, the calorie content in eggs can be roughly summarized as 55-80 calories per egg depending on size, and around 143-155 calories per 100 grams of whole egg.