A medium banana has 105 calories , 27 grams of carbs, and 422.4 mg of potassium. It is also a good source of fiber and low in fat, cholesterol, and sodium. A small banana of 101 grams contains 90 calories, while a large banana contains 135 calories .Explore their Banana calorie breakdown by size and ripeness, and find out their health advantages. Banana nut bread is a delightful treat enjoyed by many, but its calorie content can vary depending on ingredients and portion size. On average, a slice of banana nut bread contains around 200-250 calories . However, homemade recipes or bakery versions may differ in calorie count based on factors like added sugar, nuts, and oil or butter. To keep calories in check, consider using ripe bananas for natural sweetness, reducing added sugars, and opting for healthier fats like olive oil or Greek ... There are 89 calories in 100 grams of Bananas. Get full nutrition facts and other common serving sizes of Bananas including 1 oz and 1 extra small.