A banana contains calories that vary depending on its size:

• Extra small (under 6 inches, ~81 grams): about 72 calories
• Small (6–7 inches, ~101 grams): about 90 calories
• Medium (7–8 inches, ~118 grams): about 105 calories
• Large (8–9 inches, ~136 grams): about 121 calories
• Extra large (over 9 inches, ~152 grams): about 135 calories

On average, a medium banana contains approximately 100–105 calories

. Most of the calories in a banana come from carbohydrates (about 90-93%), with small amounts from protein and fat. The carbohydrate content ranges from about 19 grams in an extra small banana to 35 grams in an extra large one, including 2–4 grams of fiber

. The calorie content can also vary slightly depending on the banana's ripeness due to changes in starch and sugar composition