A medium banana (about 126 grams or 4.5 ounces) has 110 calories and 30 grams of total carbohydrates. That makes it one of the more carb-dense fruits you can grab, but the type of carbohydrate shifts dramatically depending on how ripe the banana is.
Calories and Carbs by Banana Size
The 110-calorie, 30-gram-carb figure from the FDA is based on a medium banana, roughly 7 to 8 inches long. Since bananas vary quite a bit in size, here’s how the numbers scale:
- Extra small (under 6 inches, ~80 g): about 70 calories, 19 g carbs
- Small (6–7 inches, ~100 g): about 90 calories, 23 g carbs
- Medium (7–8 inches, ~126 g): 110 calories, 30 g carbs
- Large (8–9 inches, ~135 g): about 120 calories, 31 g carbs
- Extra large (9+ inches, ~150 g): about 135 calories, 35 g carbs
The calorie-to-weight ratio stays consistent across sizes at roughly 0.9 calories per gram, so you can estimate quickly if you have a kitchen scale.
Full Nutritional Breakdown
Beyond carbs, a medium banana is almost entirely carbohydrate with very little protein or fat. You’re looking at about 1.3 grams of protein and less than half a gram of fat. It also delivers around 3 grams of fiber, which means the net (digestible) carbohydrate count is closer to 27 grams.
Where bananas stand out nutritionally is potassium. A single medium banana provides about 450 mg, roughly 10% of what most adults need daily. They’re also a good source of vitamin B6, which your body uses to metabolize protein and produce red blood cells.
How Ripeness Changes the Carbs
The 30 grams of carbohydrate in a banana don’t stay the same as the fruit ripens. A green banana stores most of its carbs as starch, a complex carbohydrate that your body breaks down slowly. As the banana turns yellow and then develops brown spots, enzymes convert that starch into simple sugars.
By the time a banana is fully ripe (solid yellow, maybe a few spots), it contains only about 1% starch by weight. The rest of the carbohydrate has become sugar, totaling roughly 23% of the banana’s fresh weight. Sucrose makes up more than 70% of those sugars in a ripe banana, with glucose and fructose splitting the remainder in roughly equal amounts.
In overripe bananas (heavily spotted or browning), the starch drops to essentially zero. The total sugar stays around 23%, but the composition shifts: sucrose drops to about half the total sugars, while glucose and fructose levels rise. This is why overripe bananas taste noticeably sweeter even though the total carbohydrate count hasn’t really changed.
For anyone watching blood sugar, this matters. A greener banana releases its energy more gradually because your digestive system has to work harder to break down the resistant starch. A very ripe banana delivers those same carbs as readily available sugar, which can cause a faster spike in blood glucose.
How Bananas Compare to Other Fruits
Bananas are often singled out as a “high-carb” fruit, and the reputation is earned when you compare similar portions. One cup of chopped apple (125 g) has about 65 calories and 17 grams of carbs. One cup of orange sections (180 g) comes in at 85 calories and 21 grams of carbs. A medium banana lands well above both at 110 calories and 30 grams.
Part of this difference is density. Bananas have less water content than apples or oranges, so the same weight packs in more carbohydrate. If you’re counting carbs for diabetes management or a keto diet, a banana takes up a bigger chunk of your daily budget than most other fresh fruits. On the other hand, if you want quick, portable energy before a workout or to recover afterward, that concentrated carbohydrate is exactly the point.
Practical Carb Counting Tips
If you’re tracking macros, the simplest approach is to weigh the banana without the peel. The peel accounts for roughly 35% of the total weight, so a banana that feels large on the outside may have a medium-sized interior. Most nutrition apps default to a 118–126 gram peeled banana for “medium,” so adjust up or down if yours looks significantly bigger or smaller.
Freezing a banana for smoothies doesn’t change its calorie or carb count. Drying it does concentrate the numbers significantly per serving, since you’re removing water. A quarter cup of dried banana chips can easily match or exceed the carbs in a whole fresh banana, often with added oil and sugar on top.