Bananas are one of the most popular fruits around, and the question of how many calories they contain comes up often for anyone tracking what they eat. The answer isn’t as simple as it might seem, since a banana’s calorie count depends noticeably on its size and, less obviously, on how ripe it is.

Calories by size

A medium banana (about 118-120 g without the peel) has roughly 105 calories. A small banana, around 6 inches long, comes in closer to 90 calories, while a large one, over 8 inches, can run 120-135 calories. The gap between the smallest and largest bananas typically found at the store can be 40-50 calories, so anyone counting calories precisely is better off going by the weight of the peeled banana rather than just “one banana.”

What makes up a banana’s calories

Carbohydrates account for the large majority of a banana’s calories. Protein contributes a small amount, and fat contributes almost nothing, since bananas contain very little of it. That balance makes bananas a convenient source of quick energy rather than a food that’s balanced across macronutrients on its own.

How ripeness changes the carbs

As a banana ripens, an interesting shift happens: the starch that dominates a green banana gradually converts into simple sugars — fructose, glucose, and sucrose. That’s why a ripe banana tastes noticeably sweeter than a green one. The total calorie count doesn’t change much through this process, but the type of carbohydrate does: a green banana has more resistant starch, which digests more slowly and has a smaller effect on blood sugar, while a ripe banana leans more heavily on simple sugars that are absorbed faster.

Fiber and other nutrients

Beyond calories, a banana provides a decent amount of fiber, around 3 grams in a medium one, which helps it hold off hunger longer than its calorie count alone might suggest. Bananas are also well known for their potassium content, important for heart and muscle function, and they contribute some vitamin B6 and a small amount of vitamin C.

Bananas in the context of a daily diet

For someone eating a typical daily calorie target, one banana is a relatively small slice of the day’s total, comparable in calories to a medium apple or a small handful of berries. Bananas are an easy snack to carry around thanks to their built-in peel, and their texture and flavor pair well with oatmeal, yogurt, or nut butter, which makes them a common choice for breakfast or a pre-workout snack.

Does the exact calorie count matter

For most people who aren’t tracking food down to the gram, a 20-30 calorie difference between a small and a large banana isn’t going to matter in practice. But for anyone counting calories strictly — working toward a specific calorie deficit or surplus, for example — it’s worth weighing the banana after peeling or checking the label if it’s bought pre-packaged.

Overall, bananas remain one of the easiest, most nutritious snacks around: a modest calorie count paired with fiber, potassium, and natural sweetness makes them a solid fit for nearly any diet.