A medium baked potato or raw potato with skin, weighing about 173 grams, contains roughly 900 milligrams of potassium. That supplies about 19% of the 4,700 mg U.S. Daily Value, though cooking method and portion weight affect the amount you consume.
This guide shows how size, skin, preparation, and serving measures affect your estimate, helping you compare potatoes, calculate daily potassium intake, and plan meals accurately.
Potassium in a Standard Medium Potato
A 173-gram raw potato with skin supplies about 900 mg of potassium. That amount approaches 19% of the 4,700 mg Daily Value shown on U.S. Nutrition Facts labels for adults and children age four and older.
Your personal requirement may differ because age, medications, kidney function, health conditions, and the rest of your diet affect your needs. The National Institutes of Health Office of Dietary Supplies additional guidance on individual intake and food labeling.
Why the edible portion matters
Potassium values refer to the part you eat, including the skin when the database entry includes it. Peeling removes some potato flesh and lowers the edible weight. Baking a whole potato with its skin preserves the measured portion, while draining boiled potatoes determines how much cooking liquid remains with them.
Raw and cooked values aren’t always interchangeable. Water evaporates during baking, and potatoes can absorb water during boiling. Your best estimate depends on matching the food form, preparation, and edible weight.
Detailed composition records from USDA FoodData Central let you compare raw potato with boiled or baked entries. Keep the stated serving basis in view, because a database’s “serving” may refer to 100 grams, a measured cup, or another defined portion.
How Potato Size and Variety Shape the Total
Edible weight is the strongest practical variable in a potato estimate. A small potato may weigh 100 to 150 grams, while a large potato can exceed 300 grams. Using about 400 to 450 mg of potassium per 100 grams gives you a starting point for scaling the amount on your plate.
Weight-based estimates
| Potato amount | Rough edible weight | Estimated potassium |
|---|---|---|
| 100 grams | 3.5 ounces | 400 to 450 mg |
| Small whole potato with skin | About 120 grams | About 480 to 540 mg |
| Medium whole potato with skin | About 173 grams | About 900 mg |
| Large whole potato with skin | About 240 grams | About 960 to 1,080 mg |
Keeping the skin generally increases the potato included in the eaten serving because the skin becomes part of the weighed portion. Your total still depends on the full potato weight and the amount of flesh removed.
Natural variation and measurement
Variety, maturity, storage, soil, and post-harvest handling create differences among individual potatoes. Nutrition databases provide dependable reference values, but weighing the portion on your plate gives you a more useful estimate for the potato you actually plan to eat.
Don’t assume every potato labeled “medium” weighs exactly 173 grams. You should check the weight when precision matters, especially when tracking dietary potassium for a medical reason.
A kitchen scale also helps with leftovers. Record the edible weight before adding milk, butter, cheese, gravy, or other ingredients, and avoid counting the entire recipe as one serving.
Baking Versus Boiling the Whole Potato
A potato baked with its skin usually retains more potassium than the same potato boiled in water. During boiling, some potassium can move from the flesh into the cooking water. Discarding that liquid removes part of the mineral before you eat the potato.
| Preparation | What happens | Practical effect |
|---|---|---|
| Baked with skin | Moisture escapes during heating | Usually preserves more potassium in the eaten portion |
| Boiled and drained | Potassium can enter the cooking water | The retained total depends on water contact and draining |
| Peeled before cooking | Skin and part of the outer flesh are removed | The serving you eat contains less total potato |
| Cooked in broth or gravy | Other ingredients add their own nutrients | The finished dish may differ from plain potato |
Cooking doesn’t create potassium. A medium potato doesn’t suddenly gain the mineral because you bake it; the apparent change comes from water loss, water absorption, peeling, discarded liquid, and the amount consumed.
Two 200-gram potatoes may appear similar before cooking, yet one can finish lighter after baking or heavier after boiling. Your intake depends on the cooked edible portion rather than the raw number listed beside a potato variety.
Matching preparation for a reliable comparison
Weigh the cooked potato after peeling and draining when that matches your meal. For boiled potatoes, count the portion you eat without counting discarded water. For baked potatoes, remove the skin only if you plan to leave it on the plate.
Preparation method alone doesn’t create or remove much potassium, but it can change your consumed portion through water absorption, moisture loss, peeling, or draining. Salt and toppings affect the finished dish for different reasons, so track them separately from the base potato.
Those cooking adjustments also determine how much potato fits into a measured cup or whole-potato serving.
Cup Portions and Whole-Potato Equivalents
One cup of boiled potato pieces contains roughly 600 mg of potassium, but that figure needs a matching weight. Cut potatoes pack differently, so a cup of chunks, slices, or cubes doesn’t always equal a cup of whole or mashed potato.
A medium potato with skin provides a useful reference point. Once you know that 173 grams supplies about 900 mg, you can estimate a cup portion by weighing it or checking the cooked serving weight for the specific preparation.
| Serving measure | Approximate potassium | Best use |
|---|---|---|
| Medium whole potato with skin | 900 mg | Whole-meal estimate |
| 100 grams raw potato | 400 to 450 mg | Weight-based estimate |
| One cup boiled pieces | About 600 mg | Recipe or portion comparison |
| One cup mashed potato | Varies by recipe | Requires weighing or a recipe label |
A standard serving may appear as a whole medium potato, 100 grams, or one cup of prepared pieces. You should distinguish that nominal measure from actual intake after cooking, peeling, draining, and adding ingredients.
Your kitchen scale is especially useful when a recipe combines potatoes with milk, butter, cheese, or gravy. Weigh the edible cooked potato portion, then record the other ingredients separately. This prevents you from counting the same serving more than once.
Use grams as your common unit. A 100-gram estimate provides a consistent bridge between a whole potato, a cup of pieces, and a larger dinner portion.
Mashed potato is harder to estimate because its final weight depends on the recipe. Weigh only the cooked potatoes before adding liquid or fat, or use the nutrition label for the complete prepared serving. Don’t mix the two methods when calculating your daily total.
Putting Potato Potassium Into a Daily Total
You can calculate the contribution from a medium potato by dividing 900 mg by 4,700 mg and multiplying by 100. Your result is roughly 19.1% of the Daily Value, while a 100-gram portion contributes about 8.5% to 9.6%.
Count only the potato portion you actually eat. In a casserole, measure the cooked potato weight before dividing the total among servings. At a restaurant, estimate the edible amount rather than assigning the entire recipe to one plate.
A practical tracking method
- Weigh the edible portion: Record grams after peeling, if you peel, and before adding other ingredients.
- Choose one database value: Match the food form, preparation, and raw or cooked weight.
- Multiply weight by concentration: At 425 mg per 100 grams, 200 grams supplies about 850 mg.
- Add meaningful ingredients: Include dairy, broth, beans, or sauces that change the total.
- Track what you eat: Count the serving on your plate rather than the full recipe.
Your calculation doesn’t need to pretend that every potato is identical. A labeled estimate is usually more useful than an overly precise number based on appearance alone. Record the weight, preparation, and estimated potassium so you can repeat the method.
When medical guidance takes priority
You should seek individualized advice from a qualified clinician or dietitian when managing potassium for medical reasons. A Daily Value supports general planning, but it can’t account for your medical care, laboratory results, or medications.
That distinction matters because a clinician may recommend a target different from the label value. Guidance from Mayo Clinic can help explain why personal potassium advice may differ, but it doesn’t replace advice tied to your health record.
That daily total becomes more useful when potatoes are weighed against other foods commonly eaten for potassium.
Comparing Potatoes and Other High-Potassium Choices
Sweet potatoes and other potassium-rich vegetables should be compared by edible weight rather than serving name alone. A baked medium sweet potato and a baked medium white potato can have different weights, moisture levels, and nutrient concentrations, even when both are called one serving.
| Food choice | Comparison point | Planning consideration |
|---|---|---|
| White potato with skin | About 400 to 450 mg per 100 grams | Use the cooked edible weight |
| Sweet potato | Varies by size and preparation | Use matched cooked weights |
| Beans or lentils | High-potassium plant protein | Add their potassium to the meal total |
| Milk or yogurt | Adds potassium and other nutrients | Include the portion you consume |
| Gravy or cheese sauce | Can change a potato dish substantially | Separate the base potato from toppings |
Portion size can affect the finished meal more than the base vegetable. A small potato topped with cheese, sour cream, and gravy may contain more potassium than a larger plain baked potato. Start with the cooked weight and add ingredients that materially change the total.
Comparing complete meals
You can compare two foods accurately when you match their edible weights and preparation. Weigh a baked sweet potato and a baked white potato after removing skins or other inedible parts. Apply a matching potassium value to each weight rather than relying on “medium.”
Detailed composition values from USDA FoodData Central support these calculations. Practical food composition resources from the Food and Nutrition Information Center at the University of Georgia can also help you interpret labels and portions. Treat every database figure as a reference estimate.
Key Takeaways
Use about 900 mg for a medium raw or baked potato with skin, 400 to 450 mg per 100 grams, or roughly 600 mg for a cup of boiled pieces. Weigh your edible portion, account for skin and cooking liquid, and compare foods by weight.
Your best starting point depends on what you’re measuring. Use a whole-potato figure for a simple meal, a weight-based value for recipes, and a label for a prepared dish. One consistent method makes your daily estimate easier to compare and revise.
FAQ
How much potassium is in one medium potato?
At about 173 grams, a medium raw potato with skin contains roughly 900 mg of potassium. That supplies about 19% of the 4,700 mg U.S. Daily Value for adults and children age four and older.
Does potato size affect the amount of potassium?
Yes. A small potato weighing about 120 grams may supply 480 to 540 mg, while a large potato weighing about 240 grams may supply 960 to 1,080 mg. Weigh the edible portion because a potato labeled “medium” may not weigh exactly 173 grams.
How much potassium does a baked potato contain compared with a boiled potato?
A potato baked with its skin usually retains more potassium than the same potato boiled in water, because some potassium can enter the cooking liquid. Your consumed amount depends on the final edible weight and whether you drain or discard the liquid.
What is a standard serving of potatoes?
One medium whole potato, 100 grams, or one cup of prepared pieces represents a standard serving. You should compare the serving’s raw or cooked weight because cup measures can vary by cut and preparation.
How much potassium do adults generally need each day?
The U.S. Daily Value used on Nutrition Facts labels is 4,700 mg of potassium for adults and children age four and older. Your personal target may differ because health, medications, kidney function, and diet affect individual needs.
Are sweet potatoes higher or lower in potassium than regular potatoes?
Sweet potatoes can provide a comparable amount, but the answer depends on weight, preparation, and variety. Compare their cooked, edible portions rather than relying on the word “medium” alone.
