Banana Calories and Nutrition by Size: Are Bananas Healthy?

Banana calories depend on size: a medium banana (7 to 8 inches) has about 105 calories in USDA data, an extra small one about 72 and an extra large one about 135. Most of those calories come from carbohydrate, a mix of natural sugars and starch that shifts as the fruit ripens. Bananas also bring fiber, vitamin B6, vitamin C and potassium, though perhaps less potassium than their reputation suggests. Below are banana calories for every size, full banana nutrition per medium fruit, what ripeness changes, and a balanced answer to the question: are bananas healthy?

Peptide Labs does not sell bananas or banana products. This article is general nutrition information, not medical advice.

Banana calories by size

USDA FoodData Central (SR Legacy, FDC ID 173944) lists raw bananas with standard sizes measured by length. The table shows banana calories, carbohydrate, sugars and fiber for each size, with the Daily Value for fiber in brackets.

Per 100 grams, raw banana has 89 calories. Bananas are almost fat-free (about 0.4 grams in a medium fruit) and low in protein (about 1.3 grams). The calories in a banana change a lot once it is dried or fried: USDA lists dehydrated banana (FDC 173945) at 346 calories per 100 grams and banana chips (FDC 168849) at 519, with 33.6 grams of fat, because chips are usually fried in oil. One ounce of banana chips has about 147 calories, more than a medium fresh banana.

Banana nutrition: vitamins and minerals

Here is banana nutrition for one medium raw banana, with the percentage of the FDA Daily Value.

The headline nutrient is vitamin B6, at about a quarter of the Daily Value. Manganese, fiber and vitamin C each land around a tenth of the Daily Value. For more vitamin C per bite, our kiwi guide shows a fruit with over a full day’s Daily Value per 100 grams.

Banana potassium in context

Bananas are famous for potassium, and a medium one has 422 milligrams in USDA data, about 9% of the Daily Value. That is useful, but by FDA labeling rules a food needs 20% of the Daily Value per serving to count as high in a nutrient, and in USDA data foods such as lentils, white beans, plain yogurt, beet greens and baked acorn squash supply more per typical serving. Our potassium foods list ranks them with USDA data, and our potassium guide covers the mineral itself.

Sugar, starch and ripeness

A medium ripe banana has about 14.4 grams of total sugars (roughly equal parts fructose and glucose, plus some sucrose) and about 6.3 grams of starch in the USDA entry. These are natural sugars within whole fruit, which the Dietary Guidelines do not count as added sugars. How a banana tastes depends heavily on ripeness:

• Ripening turns starch into sugar: a 2026 plant biology study describes the conversion of starch into sugar as the defining change in ripening bananas, and a 2023 study notes that sucrose made from starch becomes a main sweetener in the ripe fruit.
• USDA shows the same shift in plantains: SR Legacy has no separate entry for green dessert bananas, but its plantain entries, a starchy cooking relative, show it clearly: green raw plantain has about 32 grams of starch and 2.3 grams of sugars per 100 grams, while yellow raw plantain has about 12 grams of starch and 17.5 grams of sugars.
• Resistant starch: a 2024 review in the Journal of Diabetes Investigation lists green banana starch as a type of resistant starch, which escapes digestion in the small intestine and is fermented by gut bacteria into short-chain fatty acids. The authors note that large, well-designed trials are still needed.

If you prefer less sugar and more starch, a firmer, slightly green banana fits; if you want sweetness for baking, spotty ripe bananas deliver. Our fruit sugar comparison places bananas among other fruits, and our guide to prebiotics and probiotics explains fermentable fibers.

Are bananas healthy?

For most people, yes: bananas are a convenient whole fruit with fiber, vitamin B6, vitamin C and potassium, almost no fat or sodium, and natural sugars rather than added ones. They are portable and easy to eat, which also makes them a common pick for people eating smaller portions on a GLP-1 medicine, as our GLP-1 diet guide discusses. A few honest caveats:

• Carbohydrate load: a large banana has over 30 grams of carbohydrate. People managing blood sugar can usually include fruit but should ask their clinician or dietitian about portions; our low glycemic foods guide explains why ripeness matters.
• Kidney disease and some medicines: the NIH Office of Dietary Supplements notes that with chronic kidney disease or medicines such as ACE inhibitors or potassium-sparing diuretics, even dietary potassium can build up too high. If you have been told to limit potassium, follow your care team’s advice on bananas.
• Latex-fruit syndrome: some people allergic to natural rubber latex also react to certain fruits. A 2024 review in the Journal of Clinical Medicine found banana, avocado, kiwi and papaya were the fruits most often involved, with reported rates among latex-allergic patients ranging from 4% to 88% across studies.
• Labels: banana is not one of the nine major food allergens that US law requires companies to declare, so people who react need to read ingredient lists on smoothies, baked goods and baby foods. Swelling of the lips or throat, hives or breathing trouble after eating needs urgent care; for milder symptoms, see an allergist, and our elimination diet guide explains why testing should be supervised.

Fresh, dried and processed banana foods

• Fresh: about 105 calories per medium fruit with its water and fiber intact.
• Dried or dehydrated: the water is removed, so calories, sugars and potassium are concentrated; USDA lists 346 calories per 100 grams.
• Banana chips: usually fried and sometimes sweetened, at 519 calories per 100 grams in USDA data.
• Banana bread and smoothies: recipes often add sugar, syrup or juice; check the Nutrition Facts label for added sugars. Our agave guide explains why syrups count as added sugar even when they come from plants.

For more fiber-rich choices across food groups, see our guide to high fiber foods.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

Related guides: Agave Nectar: Nutrition, Fructose, Agave vs Honey and Is It Healthy?, Foods High in Potassium: USDA Table, Daily Value and Who Should Be Careful, Low Sugar Fruits: USDA Sugar per Serving, From Lowest to Highest, Plantain: Plantain vs Banana, Nutrition and How to Cook It.