One medium banana has about 422 mg of potassium; size shifts the count.
Bananas are handy, tasty, and known for their potassium. If you’re tracking this mineral for heart health, blood pressure, or muscle function, the number you care about sits right around the 400 mg mark for a medium fruit. That baseline comes from standard nutrition datasets that weigh a medium banana at ~118 g.
Potassium In A Single Banana: Quick Reference
Here’s a size-by-size view so you can match the fruit in your hand to a realistic number. These weights and values reflect commonly used serving sizes from public nutrition databases. Ripeness and variety can nudge the figure a bit, but the pattern holds: bigger fruit, more potassium.
| Banana Size | Typical Weight (g) | Potassium (mg) |
|---|---|---|
| Extra Small (<6 in) | 81 | ~290 |
| Small (6–6.9 in) | 101 | ~360 |
| Medium (7–7.9 in) | 118 | ~422 |
| Large (8–8.9 in) | 136 | ~485 |
| Extra Large (≥9 in) | 152 | ~540 |
| Per 100 g (reference) | 100 | ~358 |
Those figures line up with widely cited values: ~358 mg per 100 g, and ~422 mg for a medium fruit at ~118 g. The per-100-gram anchor helps you estimate any odd size you run into: weigh the peeled portion, then scale from 358 mg/100 g.
Why This Number Matters Day To Day
Potassium helps nerves fire, muscles contract, and fluids stay in balance. Many people fall short on daily intake, so produce, beans, dairy, and seafood do a lot of heavy lifting here. A banana’s 400-ish milligrams won’t carry the whole day, but it’s an easy chunk you can grab on the go.
How A Banana’s Form Changes The Potassium Count
The mineral itself doesn’t vanish with slicing or mashing. What changes is serving size. A cup of slices or mash packs more fruit into one measure than a single handheld piece, so the number climbs. Dried chips concentrate sugars and energy; the mineral scales with weight too, so small portions still add up fast.
Common Portions Beyond “One Fruit”
Use these handy numbers when a recipe calls for cups or ounces instead of single pieces.
- 1 cup, sliced (~150 g): ~537 mg
- 1 cup, mashed (~225 g): ~806 mg
- 1 oz banana chips (~28 g): ~150–180 mg (varies by brand and frying/baking method)
How Much Of The Day’s Need Does One Banana Cover?
Food labels in the U.S. use a Daily Value of 4,700 mg for potassium. That means a medium fruit at ~422 mg lands near the 9% mark. You’ll see that %DV on many packs and produce stickers. If you like the deeper dive on labeling, the FDA’s consumer handout spells out the current %DV math; the PDF is clear and short—link below.
Public health guidance for daily intake also appears in federal fact sheets. Adults often target the 2,600–3,400 mg range based on sex and life stage, set by U.S. nutrition authorities and summarized by the NIH Office of Dietary Supplements (link below). That’s a food-first target, not a cue to chase pills.
Two Trusted References You Can Use
Check the NIH potassium fact sheet for daily needs by age and life stage, and see the FDA’s Nutrition Facts label guide that lists the 4,700 mg Daily Value.
How Ripeness, Variety, And Prep Can Nudge The Number
Ripeness: As starches turn to sugars, weight and water shift slightly. Potassium stays in the pulp, so changes tend to be small for the same gram weight.
Variety: The common Cavendish dominates grocery bins. Red and baby types sit in the same ballpark per 100 g. If your fruit is much larger or smaller than “medium,” use the table to scale.
Prep: Cooking in water can leach minerals in some foods. Bananas are usually eaten raw, so losses aren’t a big worry. Baking in quick breads spreads the mineral through the loaf; the pan still holds it.
How To Hit Your Daily Potassium With Real Food
A banana is a solid start, but most people need several sources across the day. Try pairing fruit with leafy greens, beans, potatoes, dairy or yogurt, and fish. That mix keeps sodium in check and keeps you from leaning on a single food for the whole tally.
Smart Pairings That Stack The Count
- Oatmeal + banana slices: Add milk or yogurt to lift potassium and protein together.
- Greek yogurt parfait: Mix banana, berries, and chopped nuts; tasty and filling.
- Baked potato + salsa: Toss banana into your day as a snack to round out the total.
- Bean bowl at lunch: White beans, tomatoes, and greens carry hefty numbers per cup.
- Salmon with a side: Fish plus a starchy veg helps you cruise past the halfway point.
Label Reading Tips For Shoppers
Fresh produce doesn’t always print potassium on the sticker, but many chains now do. When you see a %DV, it’s pegged to 4,700 mg. If the card says “10%,” that’s ~470 mg. For packaged items with bananas—yogurts, smoothies, bars—scan serving size first. A bottle with two servings can double the number fast.
Recipe & Meal Math: Quick Ways To Estimate
Cooking and baking often call for cups, not pieces. Here are quick conversions that keep you on track when measuring by volume or ounces.
| Serving | Approx. Weight (g) | Potassium (mg) |
|---|---|---|
| 1 Cup, Sliced | 150 | ~537 |
| 1 Cup, Mashed | 225 | ~806 |
| Half A Medium Fruit | ~59 | ~210 |
| 2 Medium Fruits | ~236 | ~844 |
| Banana Chips (1 oz) | 28 | ~150–180 |
Banana Potassium Vs. Other Everyday Foods
Many foods can match or beat a banana gram for gram. Cooked greens, beans, potatoes, and dairy can move the needle fast. That’s good news if you want variety. A banana gives you a steady baseline; the rest of the plate can carry you to the finish.
Simple Swaps That Keep Things Balanced
- Swap a second banana for a cup of white beans: beans can land near 800–1,000 mg per cup.
- Add a baked potato at dinner: often 600–900 mg, depending on size.
- Pick yogurt as a snack: brands vary, but many single cups add 300–500 mg.
Common Questions People Ask
Is A Banana “High” In Potassium?
By label terms, a single medium fruit lands near 9% DV. That’s a solid contribution from one item. If you eat two through the day, you’re close to a fifth of the label target before counting the rest of your meals.
Do Smoothies Change The Number?
Blend it and you keep the mineral. A smoothie’s total comes from what you drop in the blender. Add milk or yogurt and the number climbs; add a pinch of salt and you push the sodium-to-potassium ratio the wrong way.
What If I’m Limiting Potassium?
Some people need tighter caps under medical care. If you’ve been asked to watch intake, stick with smaller fruit, or split a medium banana with a friend. Cooking methods that drain liquid don’t apply here, so portion size is your main lever.
How This Guide Was Built
The numbers here pull from public datasets that dietitians and researchers use every day. For bananas, the per-100-gram figure sits near 358 mg, and a medium fruit at ~118 g aligns with ~422 mg. Those entries are mirrored across nutrition tools that source the USDA database. The Daily Value figure (4,700 mg) comes from FDA labeling rules, which your Nutrition Facts panel uses to show %DV.
Takeaway You Can Use Right Now
Grab a medium banana and you’re adding ~422 mg of potassium to your day. Scale up or down using the tables, mix in beans, potatoes, dairy, and greens, and you’ll reach your target with ease—no calculator needed.
Data references: USDA-sourced entries compiled by MyFoodData (bananas) and NIH guidance on intake at the NIH ODS potassium page. Daily Value per the FDA’s consumer label guide.