How much protein is in a banana?

A banana has 1.1 g of protein per 100 g and 1.3 g per 1 medium (7" to 7-7/8" long) (118 g). That is 1.2 g of protein per 100 kcal — essentially not a protein source.

Where do these calorie figures come from?

USDA FoodData Central record 173944, “Bananas, raw” (SR Legacy, FDC SR Legacy 2018-04 + FNDDS 2024-10-31). Energy is USDA nutrient 1008 (Energy, kcal); protein, fat and carbohydrate are read from the same record. USDA data is in the public domain, and the FDC ID above links straight to it.

All foods

Bananas, apples and avocadosUSDA SR LegacyFDC 173944

Calories in a banana

USDA FoodData Central record for “Bananas, raw” — per 100 g, per every USDA serving size, and next to the other bananas, apples and avocados rows.

The short answer

A banana: 89 kcal per 100 g. 1 medium (7" to 7-7/8" long) (118 g) is 105 kcal with 1.3 g of protein. Source: USDA FoodData Central record 173944, "Bananas, raw".

Per 100 g

Nutrient	Per 100 g	Share of energy
Energy	89 kcal	100%
Protein	1.1 g	4%
Fat	0.3 g	3%
Carbohydrate	22.8 g	93%

A banana is 89 kcal per 100 g in USDA FoodData Central (SR Legacy). Of that energy, about 4% comes from protein, 3% from fat and 93% from carbohydrate. That works out to 1.2 g of protein per 100 kcal — essentially not a protein source.

Per serving

The serving sizes USDA lists for this record, priced from the per-100 g figures above. Nothing here is rounded to a “portion” — the gram weight next to each label is what the calories are computed from.

Serving	Weight	Calories	Protein	Fat	Carbs
100 g	100 g	89	1.1 g	0.3 g	22.8 g
1 cup, mashed	225 g	200	2.5 g	0.7 g	51.3 g
1 cup, sliced	150 g	134	1.7 g	0.5 g	34.2 g
1 extra small (less than 6" long)	81 g	72	0.9 g	0.2 g	18.5 g
1 small (6" to 6-7/8" long)	101 g	90	1.1 g	0.3 g	23 g
1 medium (7" to 7-7/8" long)	118 g	105	1.3 g	0.4 g	26.9 g
1 large (8" to 8-7/8" long)	136 g	121	1.5 g	0.4 g	31 g
1 extra large (9" or longer)	152 g	135	1.7 g	0.5 g	34.7 g
1 NLEA serving	126 g	112	1.4 g	0.4 g	28.7 g

Compared with other bananas, apples and avocados

Food	kcal / 100 g	Protein / 100 g	Per serving
A banana	89	1.1 g	105 kcal · 1 medium (7" to 7-7/8" long)
An apple	52	0.3 g	95 kcal · 1 medium (3" dia)
An avocado	160	2 g	240 kcal · 1 cup, cubes
A Hass avocado	167	2 g	227 kcal · 1 fruit, without skin and seed

Worth knowing

A medium banana is about 118 g peeled and 105 kcal. The peel is roughly a third of the whole fruit's weight, so weigh it peeled or subtract a third. Ripeness turns starch into sugar but does not add calories.

Other tables in fruits and fruit juices

The same numbers for the foods this one usually shares a plate — or a shopping list — with.

Questions about a banana

How many calories are in a banana?: A banana: 89 kcal per 100 g. 1 medium (7" to 7-7/8" long) (118 g) is 105 kcal with 1.3 g of protein. Source: USDA FoodData Central record 173944, "Bananas, raw".
How much protein is in a banana?: A banana has 1.1 g of protein per 100 g and 1.3 g per 1 medium (7" to 7-7/8" long) (118 g). That is 1.2 g of protein per 100 kcal — essentially not a protein source.
Where do these calorie figures come from?: USDA FoodData Central record 173944, “Bananas, raw” (SR Legacy, FDC SR Legacy 2018-04 + FNDDS 2024-10-31). Energy is USDA nutrient 1008 (Energy, kcal); protein, fat and carbohydrate are read from the same record. USDA data is in the public domain, and the FDC ID above links straight to it.

How calorie.one logs it

Type “banana” into calorie.one and the app matches this exact record — “Bananas, raw” — estimates the grams, and shows the line with its USDA label. You correct the amount; the per-100 g figure is never guessed. That split between recognition and arithmetic is the whole methodology. For the numbers in context, read How many calories are in a banana?.