Bananas are one of the most popular fruits in the world.

They are extremely healthy and contain several important nutrients.

People generally know that bananas are very nutritious, but many wonder how many calories and carbs they actually contain.

This article answers those questions.

How many calories are in various sizes of bananas?

A medium banana contains 105 calories, on average.

However, different sizes of bananas contain varying numbers of calories.

Below are the calorie contents of standard banana sizes (1):

  • Extra small (shorter than 6 inches, 81 grams): 72 calories
  • Small (6–7 inches, 101 grams): 90 calories
  • Medium (7–8 inches, 118 grams): 105 calories
  • Large (8–9 inches, 136 grams): 121 calories
  • Extra large (9 inches or longer, 152 grams): 135 calories
  • Sliced (1 cup, 150 grams): 134 calories
  • Mashed (1 cup, 225 grams): 200 calories

If you’re unsure about the size of your banana, you can estimate that an average banana contains about 100 calories.

About 93% of a banana’s calories come from carbs, 4% from protein, and 3% from fat.

Summary

The calorie content of a banana ranges from 72–135 calories depending on its size. An average-sized banana contains about 100 calories.

How many carbs are in a banana?

Bananas are almost exclusively composed of water and carbs.

People who watch their carb intake are interested in knowing the carb content of their food.

Here is the carb content of standard banana sizes (1):

  • Extra small (shorter than 6 inches, 81 grams): 19 grams
  • Small (6–7 inches, 101 grams): 23 grams
  • Medium (7–8 inches, 118 grams): 27 grams
  • Large (8–9 inches, 136 grams): 31 grams
  • Extra large (9 inches or longer, 152 grams): 35 grams
  • Sliced (1 cup, 150 grams): 34 grams
  • Mashed (1 cup, 225 grams): 51 grams

A banana also contains 2–4 grams of fiber, depending on its size. You can subtract 2–4 grams if you are looking for the “net” carb content (net carbs = total carbs – fiber).

Additionally, a banana’s ripeness may affect its carb content.

Generally, green or unripe bananas contain fewer digestible carbs than ripe bananas.

Summary

An average-sized banana contains about 25 grams of carbs — maybe even less if the banana is unripe (green).

Unripe (green) bananas contain more resistant starch

The main nutrient in bananas is carbs, but the carb composition changes drastically during ripening.

Unripe bananas contain high amounts of starch, and some of it is resistant starch (2).

Because the starch in a banana is converted to sugar during ripening, yellow bananas contain much less resistant starch than green ones. In fact, the resistant starch content of a fully ripe banana is less than 1% (2).

Resistant starch is a type of indigestible carbohydrate that escapes digestion and functions like fiber in the body.

It reaches the colon undigested. There, it feeds friendly gut bacteria (3, 4).

When the bacteria digest resistant starches, they form gases and short-chain fatty acids (SCFAs), which are important for digestive health (5, 6).

About 95% of these SCFAs are then rapidly absorbed by the cells in the colon and used by the body for energy (5, 7, 8, 9).

So although resistant starches will not yield as many calories as regular carbs during digestion, they may be transformed into SCFAs that provide calories later.

Therefore, green and yellow bananas may provide similar amounts of calories in the end.

Summary

Unripe bananas contain high amounts of resistant starch. Resistant starch escapes digestion and feeds the friendly bacteria in your gut, which use it to produce short-chain fatty acids.

Bananas contain many other beneficial nutrients

Bananas contain good amounts of several vitamins and minerals.

One medium banana contains (1):

  • Fiber: 3.1 grams
  • Vitamin B6: 25% of the DV
  • Vitamin C: 11% of the DV
  • Manganese: 14% of the DV
  • Potassium: 12% of the DV
  • Folate: 6% of the DV
  • Riboflavin (vitamin B2): 5% of the DV

Bananas are tasty and nutritious. They make an excellent, healthy, and low calorie snack.

Summary

Bananas contain good amounts of fiber, vitamin B6, manganese, vitamin C, folate, and potassium.

The bottom line

Bananas generally contain 72–135 calories and 19-35 grams of carbs, depending on their size.

An average-sized banana contains about 100 calories and 25 grams of carbs.