How much fiber in a banana, by size and ripeness

A medium banana (about 118 grams, peeled) has roughly 3.1 grams of fiber. Size moves that number more than anything else — about 2.1 g in an extra small banana, 4 g in an extra large. That works out to around 11% of the 28 g Daily Value.

How much fiber in a banana, by size

USDA food composition data puts raw banana at 2.6 g of dietary fiber per 100 g. Banana fiber grams track weight almost exactly, so the database's length-based sizes convert cleanly. Weights below are the peeled, edible portion:

• Extra small (under 6 inches, ~81 g) — 2.1 g
• Small (6 to 6⅞ inches, ~101 g) — 2.6 g
• Medium (7 to 7⅞ inches, ~118 g) — 3.1 g
• Large (8 to 8⅞ inches, ~136 g) — 3.5 g
• Extra large (9 inches or longer, ~152 g) — 4.0 g

By volume, a cup of sliced banana (about 150 g) lands near 3.9 g; a cup of mashed banana (about 225 g) near 5.8 g.

Are bananas high in fiber?

Not by the labeling definition. Under FDA nutrient content claim rules, a food needs at least 10% of the 28 g Daily Value — 2.8 g per serving — to call itself a "good source" of fiber, and at least 20% — 5.6 g — to call itself "high in fiber." A medium banana's 3.1 g clears the first bar and misses the second by a wide margin.

That makes a banana a moderate contributor rather than a fiber food. Its reputation rests more on potassium and portability.

Banana fiber content vs pear, apple, and raspberries

Per 100 grams, a banana slightly beats an apple. Per serving it loses, because the apple you pick up is bigger.

Fruit	Typical serving	Fiber	% of 28 g DV	Fiber per 100 g
Banana	1 medium (118 g)	3.1 g	11%	2.6 g
Apple, with skin	1 medium (182 g)	4.4 g	16%	2.4 g
Pear, with skin	1 medium (178 g)	5.5 g	20%	3.1 g
Raspberries	1 cup (123 g)	8.0 g	29%	6.5 g

Raspberries are the outlier — seeds plus a high skin-to-flesh ratio put them at more than double a banana's density. Pear is the quiet winner among everyday fruit: one medium pear with the skin on comes within a hair of the "high fiber" threshold on its own. The rest of the higher-fiber fruits are worth knowing by heart.

Green banana resistant starch and what ripening changes

An unripe banana is mostly starch. A ripe one is mostly sugar. Ripening enzymes convert the starch into sucrose, glucose, and fructose, which is why a spotted banana tastes sweet and a green one tastes chalky and dry.

Much of the starch in a green banana is resistant starch: it escapes digestion in the small intestine and gets fermented by bacteria in the colon, behaving a lot like a fermentable fiber. By the time the peel is freckled, most of that has been converted and the fermentable payload is largely gone.

One caveat keeps this honest: the printed fiber figure barely changes with ripeness, because the standard assay behind most food databases doesn't fully capture resistant starch. What reaches the colon shifts even when the grams on the label don't.

What kind of fiber a banana contains

A mix. Pectin is the soluble component, and it breaks down as the fruit softens — the same process that turns a firm banana mealy. Cellulose and hemicellulose make up the insoluble side and survive ripening intact. Neither type is better; they do different jobs, covered in soluble vs insoluble fiber.

Where a banana fits in a day's target

The Adequate Intake set by the National Academies works out to 14 g of fiber per 1,000 calories — about 25 g a day for adult women and 38 g for adult men under 50. Labels use a flat 28 g Daily Value. Against those published figures, a medium banana covers roughly an eighth of a woman's target and a twelfth of a man's: a component of a day's fiber intake, not a strategy.

Pairing is what moves the total: banana with oats, banana with chia, banana sliced onto a bran cereal. Logging by size helps too, since the spread from extra small to extra large is nearly 2 g — enough to drift meaningfully over a week of eyeballed entries. Fiber Tracker is a fiber tracking app for iPhone, where per-serving grams get logged by size instead of guessed.

FAQ

Are bananas high in fiber?

No. A medium banana has about 3.1 g, which is roughly 11% of the 28 g Daily Value. FDA rules reserve "high fiber" for servings with 20% or more, so a banana qualifies as a good source but not a high-fiber food.

How much fiber is in a banana compared to an apple?

A medium banana has about 3.1 g; a medium apple with the skin has about 4.4 g. The gap comes from serving size rather than density — per 100 grams the two are nearly identical, and the banana is marginally ahead.

Do green bananas have more fiber than ripe ones?

Measured fiber is about the same. What differs is resistant starch: a green banana carries a lot of it, and ripening converts most of it to sugar. Resistant starch ferments in the colon much like fiber does, but standard label testing doesn't fully count it.

How many bananas would it take to hit the daily fiber target?

Eight to twelve, depending on size and which target you use — which is exactly why bananas aren't a practical route. Beans, whole grains, and berries do the heavy lifting in most patterns that reach 25–38 g.

Does blending a banana into a smoothie destroy its fiber?

No. Blending breaks the fiber into smaller pieces but doesn't remove it, so the grams in the glass match the grams in the fruit. Juicing is the process that strips fiber out, and bananas aren't typically juiced.