A medium banana (118g) has 105 calories, 27g of carbs, 1.3g of protein, and 3.1g of fiber, according to USDA FoodData Central. That is the number your tracking app shows by default, and it is correct - for a banana measuring 7 to 7⅞ inches.
The catch is that USDA publishes five official banana sizes, and the gap between the smallest and the largest is 63 calories. If a banana is part of your daily routine, logging the wrong size adds up quietly. Here is the full breakdown by size, how bananas stack up against other fruits, and the processed forms where the real calories hide.
Banana Calories by Size
These are USDA's official size classes with their gram weights. Weights are for the fruit only - peel off.
| Size | Length | Weight | Calories |
|---|---|---|---|
| Extra small | under 6" | 81g | 72 |
| Small | 6" to 6⅞" | 101g | 90 |
| Medium | 7" to 7⅞" | 118g | 105 |
| Large | 8" to 8⅞" | 136g | 121 |
| Extra large | 9" or longer | 152g | 135 |
| 1 cup, sliced | - | 150g | 134 |
| 1 cup, mashed | - | 225g | 200 |
Source: USDA FoodData Central, Bananas, raw (FDC ID 173944), 89 calories per 100g.
A medium banana also carries about 14g of natural sugar and 422mg of potassium - roughly 9% of the daily value.
Nobody Weighs a Banana
Here is the honest problem with that table: you have no idea which row you are eating. Almost everyone logs "1 medium banana" regardless of what is in their hand, and grocery store bananas often run large or extra large. Log a 9-inch banana as a medium every morning and you are off by 30 calories a day - small, silent, and always in the same direction.
This is the fruit version of the weighing mistake that quietly wrecks calorie counts: the database number is right, but the food on the scale is not the food you logged. The fix takes ten seconds. Peel one banana, put it on the scale, and see which USDA row your store actually sells. You do not need to weigh every banana forever - you need to calibrate your eyeball once.
How Bananas Compare to Other Fruits
Per 100g, bananas sit at the calorie-dense end of common fresh fruits - less water, more starch:
| Fruit (raw) | Calories per 100g |
|---|---|
| Banana | 89 |
| Grapes | 69 |
| Apple | 52 |
| Orange | 47 |
| Strawberries | 32 |
| Watermelon | 30 |
Source: USDA FoodData Central, SR Legacy entries.
Per piece, the gap shrinks: a medium banana is 105 calories, a medium apple is 95, and a medium orange is 62. The banana's density cuts both ways - it is more filling per piece than lighter fruits, it just is not the pick when you want maximum volume for minimum calories. If that is the goal, watermelon wins at 30 calories per 100g.
Where Banana Calories Actually Hide
No one struggles with weight because of whole bananas. The processed forms are a different food:
- Banana chips: 519 calories per 100g - nearly six times the fresh fruit. They are fried, and a third of their weight is fat from the frying oil. A modest 1 oz handful is 147 calories, more than an extra-large fresh banana.
- Smoothies. The banana is the cheap part: 105 calories. Add 2 tablespoons of peanut butter (191 calories), a cup of juice, a spoon of honey, and the "fruit smoothie" clears 400. A banana with 1 tablespoon of peanut butter eaten as-is is about 201 calories - the same flavor with a scale under it. More ideas like that in our snacks under 200 calories list.
- Frozen banana "ice cream." This one hides in your favor: one frozen medium banana blended until creamy is 105 calories, versus 137 for half a cup of vanilla ice cream.
Sliced over oatmeal, a banana is one of the cheapest breakfast upgrades there is - just log the size you actually used.
Does Ripeness Change the Calories?
Barely. USDA's standard entry for raw bananas is 89 calories per 100g, and its separate analysis of overripe bananas comes in at 85. What ripening really changes is the form of the carbs: resistant starch converts to simple sugars, which is why a spotty banana tastes sweeter and digests faster. The calories stay put; only the texture and the glycemic response move.
The Bottom Line
A banana has 72 to 135 calories depending on size, and 105 is only correct for a true 7-inch medium (USDA). Bananas fit easily into a calorie deficit - they come pre-portioned, they travel, and they handle a sugar craving for about 100 calories. Get your daily target from the daily calorie calculator, then do the ten-second calibration: peel your next banana, weigh it, and find your row in the table above.
