A medium banana contains about 450 mg of potassium. That’s roughly 13% of the daily recommended intake for adult men and 17% for adult women, making bananas one of the most convenient sources of this essential mineral.
Potassium by Banana Size
The 450 mg figure comes from a standard medium banana, which weighs about 115 grams of edible fruit after peeling. Since potassium content scales with weight, a smaller banana (around 90 grams of fruit) delivers closer to 350 mg, while a large one (around 135 grams) can reach 530 mg or more. If you’re tracking your intake closely, size matters more than you might expect.
Ripeness Doesn’t Change Potassium Levels
A green banana and a spotty brown one contain essentially the same amount of potassium. Research tracking Cavendish bananas through nine ripening stages found no meaningful change in potassium concentration from unripe to overripe. What does change is the sugar and starch balance: green bananas have more resistant starch, while ripe bananas convert that starch to sugar. But the mineral content stays stable, so pick whatever ripeness you prefer without worrying about potassium.
How Bananas Compare to Other Foods
Bananas have a reputation as the go-to potassium food, but several everyday foods actually deliver more. A large baked russet potato with skin contains about 1,644 mg of potassium, more than three times what a banana provides. A cup of cooked black beans has roughly 600 mg. Other strong sources include sweet potatoes, spinach, avocados, and dried apricots.
That said, bananas earn their reputation through convenience. They require no cooking, come in their own packaging, and pair easily with breakfast or snacks. For people who struggle to eat enough potassium-rich vegetables, adding a banana or two to your daily routine is one of the simplest fixes available.
How Much Potassium You Need Daily
The National Institutes of Health sets the adequate daily intake at 3,400 mg for adult men and 2,600 mg for adult women. Most people fall short of these targets. Eating two bananas a day would cover roughly a quarter of the goal for men and a third for women, but you’d still need other sources to close the gap.
Potassium helps regulate fluid balance, muscle contractions, and nerve signals. It also counteracts the blood pressure effects of sodium, which is why diets rich in potassium are consistently linked to lower cardiovascular risk. The mineral works best as part of a broader pattern of fruit, vegetable, and legume intake rather than from any single food.
Kidney Disease and Potassium Limits
For most people, getting more potassium from food is a good thing. The exception is anyone with chronic kidney disease or a condition called hyperkalemia, where potassium builds up in the blood because the kidneys can’t clear it efficiently. The National Kidney Foundation classifies any food with 200 mg or more per serving as “high potassium,” and bananas land well above that threshold. People managing kidney-related potassium restrictions are typically advised to limit bananas to half at a time, or avoid them altogether depending on their lab results and their care team’s guidance.
Serving size also plays a role here. Even foods considered lower in potassium can become high-potassium choices if you eat a large portion. For anyone on a potassium-restricted diet, measuring portions consistently is more important than memorizing which foods are “good” or “bad.”