A medium banana weighing about 118 grams supplies roughly 420 milligrams of potassium, equal to about 9% of the FDA Daily Value. It offers a convenient source, though portion size and your total food pattern shape the full result.
This guide covers potassium per serving, Daily Value guidance, portion differences, food comparisons, and the individual considerations that shape dietary potassium decisions.
Bananas Deserve Their Potassium Reputation
A 420-milligram serving supplies potassium for fluid balance, nerve signaling, and muscle contraction. The mineral also works alongside sodium in maintaining normal blood pressure. Your body carries out these functions continuously, even though one banana contributes only part of the total.
By everyday food standards, bananas contain a substantial amount of potassium. They rarely rank as the richest source by weight, but portability and portion control make a banana useful. One piece also brings carbohydrate, vitamin B6, vitamin C, and fiber.
The National Institutes of Health Office of Dietary Supplements lists a 4,700-milligram Daily Value for adults and children age four and older. Dividing 4,700 by 420 shows that a medium banana supplies 8.9%, which nutrition labels round to 9% or 10%.
A convenient source differs from a concentrated source. Your portion and total food pattern determine what the banana contributes.
You get the clearest answer by comparing milligrams per realistic serving with the serving’s share of your day. A ranking by 100 grams measures concentration, not the amount on your plate. That distinction can make the same food look stronger or weaker than it will contribute.
The Potassium in a Medium Banana
The 420-milligram estimate applies to edible banana flesh from fruit weighing about 118 grams with its peel attached. It does not count the peel you discard. U.S. Department of Agriculture FoodData Central entries can differ because some use another reference weight or portion.
A Complete Serving Breakdown
Potassium represents only part of what the fruit supplies. One medium banana also provides about 27 grams of carbohydrate, 3 grams of dietary fiber, 9 milligrams of vitamin C, and 0.4 milligrams of vitamin B6.
| Nutrient in a medium banana | Approximate amount |
|---|---|
| Potassium | 420 milligrams |
| Carbohydrate | 27 grams |
| Dietary fiber | 3 grams |
| Vitamin C | 9 milligrams |
| Vitamin B6 | 0.4 milligrams |
These nutrition figures are estimates, not fixed amounts attached to every banana. Ripeness and storage affect vitamin values. Peel thickness and the peel-to-flesh ratio also change the edible weight of an unpeeled banana.
Why Database Numbers Differ
You may see 400, 422, or another nearby figure because analytical samples and portions differ. FoodData Central can use a measured edible portion, a household measure, or laboratory samples drawn from several pieces.
Your estimate does not need false precision. For an ordinary 118-gram banana, 420 milligrams is a practical starting point. The same calculation stays clear: 420 divided by 4,700 equals 8.9% of the Daily Value.
Why Serving Size Changes the Potassium Picture
Two medium bananas deliver about 840 milligrams, close to 18% of the Daily Value. A very large banana can exceed 500 milligrams, while a small banana can fall below 350 milligrams. Potassium rises and falls with the amount of flesh on your plate.
Natural Variation Has Limits
Cultivar, ripeness, storage, soil, and growing conditions produce modest differences. These factors account for some database and laboratory variation. Even so, a larger banana generally contains more edible fruit and more potassium.
Ripeness changes a banana’s starch and texture without shifting it into another potassium category. A heavily browned banana remains close to the same basic amount. Its edible mass is still the main portion factor.
A Simple Adjustment Method
You can refine your estimate by comparing the banana’s edible weight with a 118-gram reference. Multiply 420 milligrams by the weight ratio, then round to the nearest 5 or 10 milligrams.
- Use a scale: Weigh the unpeeled fruit, then subtract an estimated 20% to 25% for its peel.
- Use package weight: A listed 136-gram banana contains a little more potassium than a medium banana.
- Count the portions: Two standard bananas produce an estimate near 840 milligrams.
- Drop false precision: A difference of 10 or 20 milligrams is small within dietary potassium intake across a day.
Your estimate becomes more useful beside the rest of your intake. One banana rarely supplies most dietary potassium, so foods eaten earlier and later in the day have a larger effect.
Foods With More Potassium Than a Banana
A cup of milk comes close to a banana’s potassium amount. A cup of beans, a large baked potato, or a 3-ounce fish portion can supply more. Edible quantity explains why several foods outrank a 118-gram banana.
Realistic Serving Comparisons
| Food and serving | Approximate potassium |
|---|---|
| Medium banana | 420 milligrams |
| White milk, 1 cup | 365 to 370 milligrams |
| Kidney beans, 1 cup | 670 to 700 milligrams |
| Baked potato with skin, large | 900 to 1,000 milligrams |
| Tomato, 1 cup chopped | 430 to 450 milligrams |
| Salmon, 3 ounces | 500 to 550 milligrams |
Each entry is a comparison estimate rather than a fixed promise. A medium potato differs from a large one, and draining canned beans changes their weight. FoodData Central provides standardized federal composition data, while the Academy of Nutrition and Dietetics supplies meal-planning context.
Serving Beats Concentration
Concentration describes how densely a food packs potassium by weight. Potato contains less potassium by weight than banana, yet a large potato can supply more because its edible mass is greater. Your plate can reverse a 100-gram ranking.
Bananas rank near the upper end among fruits. Dried apricots and some other fruits supply more in a smaller serving, while apples, pears, and berries generally supply less. Keeping the serving unit consistent makes each comparison easier to interpret.
This method also prevents an incomplete conclusion. Beans or potatoes supplying more does not remove the banana from the list. It gives you another food that fits your meals and existing preferences.
How the Daily Value Fits Into Daily Decisions
The 4,700-milligram Daily Value is a labeling reference, not a personal prescription. Recommended dietary allowances are about 2,600 milligrams daily for adult women and 3,400 for adult men, with amounts varying by age and sex.
A Reference Point, Not a Prescription
The Daily Value provides one shared number for labeling across the food supply. It does not set 4,700 milligrams as the right daily amount for every adult. Your target reflects age, sex, health, medications, and advice from your health care professional.
Food and drug labeling rules require potassium on Nutrition Facts panels for foods that meet the declaration threshold. A Daily Value percentage gives you a quick product comparison, but you still need to read the printed serving size before comparing portions.
A Practical Label Method
Start with the serving size on the Nutrition Facts panel. Multiply the listed Daily Value percentage by 4,700 milligrams for a broad estimate. Milligram amounts on the panel offer a more direct figure.
- Match the portion: Compare the food you plan to eat with the labeled serving.
- Convert the percentage: A 10% share equals about 470 milligrams.
- Combine your sources: Count milk, vegetables, beans, fish, and fruit across the day.
- Check the liquid: Draining canned food changes its concentration and portion weight.
- Ignore the color: Fruit color does not reliably show potassium content.
You can spread the contribution across meals. A banana at breakfast, milk with lunch, and beans, potatoes, tomatoes, or fish later can move daily dietary potassium intake past 4,700 milligrams.
For someone managing a potassium restriction, that cumulative intake makes individualized limits especially important.
When Potassium Limits Need Individual Attention
A banana is neither automatically safe nor unsafe because of its potassium content. Kidney function, blood potassium, treatment, and medication can determine how a portion fits your care plan.
Clinical Limits Differ From Daily Value Guidance
Chronic kidney disease or reduced kidney function can limit potassium clearance from the blood. A clinician may set a daily target from laboratory results such as serum potassium. Treatment may also address hypokalemia or excessive potassium accumulation.
Several classes of medicines alter potassium levels or excretion. Examples include certain diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and potassium supplements. Your prescriber or kidney specialist can place those effects in context; a food table cannot.
For a potassium restriction, use your clinician’s target, count portions, and ask a pharmacist about medicines that affect potassium.
Count Portions, Not Just Foods
Bananas, tomatoes, potatoes, oranges, dried fruit, beans, and certain prepared products add up across a day. Cooking methods, serving weights, and added ingredients also change intake. Your estimate therefore needs more than one single-food number.
You can still use 420 milligrams as a planning figure for a medium banana. Add other portions, record high-potassium choices, and share the record with your care team. Large dietary changes belong with that clinical conversation.
Weakness, muscle cramps, or an abnormal heart rhythm can accompany potassium levels that are too low or too high. A clinician can connect those symptoms with blood tests and identify the cause. A food label cannot supply that diagnosis.
Bottom Line
A medium banana supplies about 420 milligrams of potassium, around 9% of the 4,700-milligram Daily Value. Your portion size changes that amount, and foods such as beans, potatoes, milk, tomatoes, and fish can supply more in realistic servings. Individualized clinical guidance takes priority over general figures for your nutrition plan.
FAQ
Are bananas actually high in potassium?
Yes, bananas contain substantial potassium for their serving size. A medium banana supplies about 420 milligrams, though bananas rarely rank as the richest source by weight.
How much potassium is in one medium banana?
At about 118 grams, a medium banana provides roughly 420 milligrams of potassium. That equals about 9% of the 4,700-milligram FDA Daily Value. A larger banana provides more, while a smaller piece provides less.
What percentage of the Daily Value does one banana provide?
One medium banana provides about 8.9% of the 4,700-milligram Daily Value, which labels round to 9% or 10%. The listed amount also depends on the banana’s edible weight.
Are bananas considered high-potassium foods?
With roughly 420 milligrams per medium fruit, bananas are a convenient source of potassium. They rank below many other foods by weight, so a medium banana remains one useful source among fruits, vegetables, dairy products, beans, and fish.
How does banana potassium content compare with other fruits?
Bananas contain more potassium than many common fruits, including apples, pears, and berries. Dried apricots can supply more in a small portion. Serving size also affects the fiber, vitamin C, and carbohydrate delivered with each fruit.
How does banana size or serving size change the potassium content?
Potassium follows edible portion size. Two medium bananas supply about 840 milligrams, a very large banana can exceed 500 milligrams, and a small banana can fall below 350 milligrams.
