How Much Potassium Is in One Potato? A Comprehensive Nutritional Guide

November 17, 2025 •

4 min read

According to the Washington State Potato Commission, a medium (5.3 ounce) potato with the skin contains 620 mg of potassium, which is significantly more than a medium banana. This reveals that for an excellent source of this vital mineral, you don't need to look any further than the humble potato. Understanding exactly how much potassium is in one potato, and how to preserve it, can help you maximize your dietary intake for better health.

Quick Summary

A medium potato contains a substantial amount of potassium, exceeding that of a banana. Content can be influenced by variety, size, and cooking method. Baking with the skin on helps retain more nutrients, while boiling can significantly reduce potassium levels.

Key Points

Medium Potato Potassium: A medium (5.3 oz) potato with skin contains approximately 620 mg of potassium, providing about 15% of the daily value.
More Than a Banana: The potassium content in a medium potato is significantly higher than that found in a medium banana, often touted for its potassium.
Cooking Method is Key: Baking or microwaving potatoes with the skin on helps to preserve potassium levels, while boiling can cause the water-soluble mineral to leach out.
Variety Affects Content: The potassium level varies between different potato varieties. Studies have shown purple Viking potatoes can have more potassium than Idaho potatoes.
Skin's Importance: A significant amount of potassium is concentrated in and directly under the potato skin, so eating the skin on boosts nutrient intake.
Cooking for Low-Potassium Diets: For those on a restricted-potassium diet, boiling cut and peeled potatoes and discarding the water is a method used to reduce intake.

The Nutritional Breakdown: Potassium in a Standard Potato

When evaluating a potato's potassium content, it is useful to refer to a standard serving size. A medium potato, often defined as 5.3 ounces (148 grams) with the skin, is the benchmark used by many nutritional organizations. This serving provides approximately 620 milligrams of potassium. This quantity represents about 15% of the recommended daily value, making it an excellent source of the mineral. Potassium is a critical electrolyte that plays a key role in maintaining fluid balance, nerve signaling, and muscle contractions, including those of the heart. Incorporating potatoes into a balanced diet can therefore contribute significantly to meeting your daily potassium needs. Furthermore, the potato offers additional nutritional benefits, including a good source of vitamin C, vitamin B6, and dietary fiber, especially when the skin is consumed.

Size Matters: From Small to Large

Just as with any other fruit or vegetable, the size of the potato directly correlates with its potassium content. While a medium potato contains roughly 620 mg, a larger potato will naturally provide more. For example, a large baked potato (299 grams) can contain as much as 1,600 mg of potassium, offering a substantial portion of your daily recommended intake. Conversely, a smaller potato will provide a lower amount. Portion control is therefore crucial for those on potassium-restricted diets, such as individuals with advanced kidney disease.

Factors Influencing Potassium Levels

Several factors can affect the final potassium concentration in the potato you consume. These include the potato variety, the presence of the skin, and, most importantly, the cooking method.

The Impact of Cooking Methods on Potassium

How a potato is prepared can dramatically alter its potassium retention. As a water-soluble mineral, potassium can leach out of the potato and into cooking water during the boiling process.

To maximize potassium retention:

Bake or microwave with the skin on: These dry-heat methods are the most effective for preserving potassium and other water-soluble vitamins. The skin also contains a significant concentration of the mineral.
Roast instead of boil: If you prefer roasted potatoes, a quick parboil can help, but roasting alone is a better choice than prolonged boiling.

To reduce potassium content:

Boil in small pieces: For individuals on a low-potassium diet, boiling cut-up potatoes in a large pot of water and discarding the water is a common strategy to reduce the mineral content by up to 50%.
Double-boil or leach: This process involves boiling the potato, discarding the water, and boiling it again to further reduce potassium.

Comparison of Potassium Sources

Many people associate bananas with potassium, but potatoes are a nutritional powerhouse that often surpasses them. This table provides a clear comparison of how a baked potato stacks up against other well-known potassium sources.


Food Item	Serving Size	Potassium (mg)	Notes
Baked Potato (with skin)	1 medium (148g)	926	Highest retention through dry-heat cooking.
Boiled Potato (without skin)	1 cup	256	Significant loss due to boiling and peeling.
Banana	1 medium	422	A common, but less potent, source.
Sweet Potato (baked)	1 medium (130g)	440	Still an excellent source, just slightly less than a white potato.
Acorn Squash (cooked)	1 cup	896	A very high source of potassium.
Spinach (cooked)	1 cup	839	Another excellent vegetable source.

Different Potato Varieties and Potassium Levels

Not all potatoes are created equal when it comes to their mineral profile. Studies have shown that potassium content can vary significantly between different varieties. For instance, a purple Viking potato was found to have a higher potassium level (448.1 mg per 100g) than an Idaho potato (295 mg per 100g) in a raw state. Other varieties like the Yukon Gold and Red Bliss also show differing levels. These variations are influenced by factors such as soil type, growing conditions, and genetics. This provides an opportunity for dietary variety while still obtaining plenty of potassium. While the standard russet remains a fantastic source, exploring different types can offer a broader nutritional experience.

Conclusion

In summary, one medium potato is an excellent and often underestimated source of potassium. With around 620 milligrams, it provides a significant portion of the daily recommended intake, even surpassing the potassium content of a banana. Its final nutritional value, however, is highly dependent on how it's cooked, with baking and microwaving being the best methods for retention. For those who need to manage their intake, cooking methods like double-boiling can be used to reduce the mineral's presence. As a naturally affordable and nutrient-dense food, the potato is a powerful tool for promoting overall health and supporting proper bodily function. For more information on dietary minerals, visit the National Institutes of Health's Office of Dietary Supplements website.(https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/)

Frequently Asked Questions

Yes, a medium potato contains more potassium than a medium banana. A medium (5.3 oz) potato with skin offers 620 mg of potassium, while a medium banana provides about 422 mg.

Yes, peeling a potato significantly reduces its potassium content. A large portion of the potassium, along with other nutrients like fiber, is concentrated in the skin and just below it.

Boiling potatoes, especially when peeled and cut, can cause a significant loss of potassium. This is because potassium is a water-soluble mineral that leaches into the cooking water.

To retain the most potassium, bake or microwave the potato with the skin on. These methods use dry heat and do not submerge the potato in water, minimizing nutrient loss.

While both are good sources, a medium white potato generally contains more potassium than a medium sweet potato. A medium white potato has around 620 mg, compared to 440 mg in a medium sweet potato.

French fries and other processed potato products are less healthy options. Frying adds fat, and processing can reduce nutrients. They also often contain high amounts of sodium, which can counteract some of potassium's benefits.

Individuals with advanced kidney disease or those on potassium-restricted diets should monitor and, if necessary, reduce their potassium intake from high-potassium foods like potatoes. For most healthy people, consuming potassium-rich foods is beneficial.