A medium ripe banana has about 105 to 110 calories. That’s based on a banana weighing roughly 118 to 126 grams (about 4.5 ounces), which is the standard “medium” size you’d find at most grocery stores.
Calories by Banana Size
Not all bananas are the same size, and the calorie count scales with weight. Bananas are roughly 89 calories per 100 grams, so you can estimate based on how big yours is. A small banana (about 100 grams of edible fruit) comes in closer to 90 calories, while a large one (around 135 to 150 grams) can reach 120 to 135 calories. If you’re using bananas in a recipe and measuring by volume, a cup of sliced banana weighs more than a single fruit and will land around 130 to 140 calories.
For most people tracking calories casually, 105 calories for a medium banana is the number to use. It’s close enough that the difference between a slightly smaller or larger fruit won’t matter in any meaningful way.
Does Ripeness Change the Calorie Count?
This is the question behind the question, and the answer is: not really. As a banana ripens from green to yellow to spotted brown, its starch converts into simple sugars like glucose, fructose, and sucrose. A ripe banana contains only about 1% starch, while a green banana is much higher in starch. But starch and sugar contain the same number of calories per gram (about 4), so the total calorie count stays essentially the same regardless of ripeness.
What does change is how your body processes those calories. Green bananas contain more resistant starch, a type of starch that passes through your small intestine without being fully digested. This means your body may absorb slightly fewer calories from a green banana than from a ripe one, though the difference is small. A ripe banana, with its sugars already broken down, is digested and absorbed more quickly. That’s why a ripe banana tastes sweeter and gives you a faster energy boost, even though the calorie label would be identical.
What Else Is in a Ripe Banana
A medium ripe banana delivers about 28 grams of carbohydrates, 15 grams of naturally occurring sugar, and 3 grams of fiber. It has virtually no fat and only about 1 gram of protein. Bananas are almost entirely a carbohydrate food, which makes them a quick and convenient energy source before or after exercise.
The 3 grams of fiber help slow digestion enough that a banana won’t spike your blood sugar the way 15 grams of added sugar from candy would. That said, riper bananas do have a higher glycemic index than green ones, meaning they raise blood sugar a bit faster. If blood sugar management matters to you, choosing bananas that are yellow but not yet spotted will give you a middle ground between taste and slower digestion.
Beyond the macros, bananas are best known for their potassium content, and they also provide vitamin B6 and magnesium. These nutrients support normal muscle function, nerve signaling, and energy metabolism.
How Bananas Compare to Other Fruit
At 105 calories, a banana is on the higher end for a single piece of fruit. An apple of similar size has about 95 calories, an orange around 60 to 80, and a cup of strawberries just 50. The difference comes down to water content: bananas are denser and less watery than most fruits, which concentrates both their calories and their nutrients into a smaller package.
That density is exactly what makes bananas so practical. They’re portable, they don’t need refrigeration, and they come in their own wrapper. For the calories you get, you’re also getting a solid dose of potassium and fast-digesting carbs, which is why they’re a go-to snack for athletes and a staple in smoothies and oatmeal. If you’re watching total calorie intake closely, just count one medium banana as 105 calories and adjust if yours is noticeably larger or smaller than average.