How many calories are in a banana? Size chart included

A medium banana, about 7 to 8 inches long, carries roughly 105 calories. That number comes straight from the USDA FoodData Central record behind our bananas, raw page, which lists 89 calories per 100 grams. A medium banana weighs about 118 grams once you peel it, and 89 times 1.18 lands you at 105. If you only remember one number from this guide, that is the one.

But bananas are not standardized products. They range from stubby lunchbox fruit to the oversized specimens at the bottom of the grocery display, and the calorie difference between a small and an extra large banana is bigger than most people expect. Here is the full picture, size by size, followed by the sugar and potassium context that makes the calorie number actually useful.

Banana calories by size

All of the figures below use the USDA value of 89 calories per 100 grams of peeled banana. The weights are the standard USDA size categories, so you can match your banana to the chart by length.

• Extra small (under 6 inches, about 81 g): roughly 72 calories
• Small (6 to 7 inches, about 101 g): roughly 90 calories
• Medium (7 to 8 inches, about 118 g): roughly 105 calories
• Large (8 to 9 inches, about 136 g): roughly 121 calories
• Extra large (9 inches or longer, about 152 g): roughly 135 calories
• Per 100 grams, peeled: 89 calories

Two practical notes. First, these weights are for the edible portion only. The peel accounts for a meaningful share of what the scale shows, so a banana that weighs 180 grams whole is closer to a medium than a large once peeled. Second, our database lists the NLEA serving for bananas at 126 grams, which works out to about 112 calories, a touch above the classic medium. If you are logging food and want one honest default, 105 to 112 calories per banana is the range to use.

Where those calories come from

Bananas are a carbohydrate food, plain and simple. Per 100 grams, the USDA record shows 22.8 grams of carbohydrate, just 1.09 grams of protein, and 0.33 grams of fat. Nearly all of the energy in a banana arrives as carbohydrate, which is why they have long been the default fuel for runners and cyclists. The carbs digest readily, the fruit travels well, and there is no wrapper to deal with beyond the one nature provided.

Of that carbohydrate, 12.2 grams per 100 grams is sugar. Scale that to a medium banana and you get about 14 grams of sugar, alongside roughly 3 grams of fiber. That sugar is naturally occurring, packaged with fiber and water, which is a very different situation from 14 grams of added sugar in a soft drink. The fiber slows things down and adds fullness that a sweetened beverage cannot match. Still, if you are watching total sugar, it is worth knowing that a banana carries more of it than most whole fruits. Strawberries, for comparison, hold just 4.89 grams of sugar per 100 grams.

The potassium story

Ask anyone to name one nutrient in a banana and they will say potassium, and the reputation is earned. The USDA lists 358 milligrams of potassium per 100 grams, which puts a medium banana at about 422 milligrams. Bananas also contribute magnesium, at 27 milligrams per 100 grams, plus a modest 8.7 milligrams of vitamin C.

Bananas are not the single richest potassium source in our database, but they are one of the most convenient. No cooking, no prep, no refrigeration. For a portable food that delivers a solid dose of potassium with essentially zero sodium, only 1 milligram per 100 grams, the banana is hard to beat. That near-zero sodium is also why bananas carry the low-sodium tag on our food page.

How a banana scores on our density index

On the NutriVerdict Nutrient Density Score, our per-calorie 1 to 100 scale built on USDA data, bananas, raw score 45. That places them in the middle of the fruit pack, and the reason is the ratio at the heart of the score: bananas carry more calories per 100 grams than most fresh fruit, so every milligram of potassium and vitamin C is divided by a larger energy number.

Compare the neighbors. Strawberries, raw score 92, powered by 58.8 milligrams of vitamin C on only 32 calories per 100 grams. Mangos, raw score 83. Watermelon, raw lands at 59, and blueberries, raw sit at 48, just above the banana. None of this makes the banana a poor choice. A score of 45 means the banana buys its nutrition at a moderate calorie price, not that the nutrition is absent. It simply means that if you want maximum micronutrients per calorie from the fruit bowl, berries win.

Processing changes the math dramatically. Banana chips score just 10 on our index, because frying concentrates the calories while the potassium per calorie collapses. Same fruit, very different verdict.

The bottom line

A banana costs you 72 to 135 calories depending on size, with 105 as the sensible default for a medium. In exchange you get about 422 milligrams of potassium, 3 grams of fiber, and a naturally sweet, zero-prep package. It is not the most nutrient-dense fruit we track, but it is one of the most practical, and the calorie count is modest by any everyday standard. Check the full nutrient breakdown on our bananas, raw page.