Butter is one of the lowest-potassium foods in the dairy family — a standard tablespoon contains only about 3–4 mg of potassium. That makes it a welcome addition for people following a low-potassium diet for kidney health, but it is still worth tracking when you are building a precise food log or calculating daily potassium totals.
This butter potassium calculator estimates the potassium content of any serving of butter using USDA reference data (24 mg per 100 g). Simply enter the amount, choose your unit — grams, tablespoons, sticks, cups, ounces, or teaspoons — and get the potassium in milligrams plus the percentage of the daily value.
Whether you are meal planning for a cardiac or renal diet, counseling clients, or just curious how butter compares with fruits and vegetables, this quick tool gives you accurate numbers in seconds.
🧈 Butter Potassium Calculator
Estimate the potassium content of butter by weight or common household measures using USDA reference data.
📊 Results
How to Use This Tool
This calculator is designed for quick, accurate potassium logging. Start by entering a number in the Amount field, then select the unit that matches how you measured the butter. If you are using a nutrition app, grams is usually the most reliable choice because food labels and the USDA database express potassium per 100 grams. You can also click one of the preset buttons to instantly fill in a common serving size.
- Enter the amount of butter in the number field.
- Choose the matching unit from the dropdown: grams, tablespoons, teaspoons, sticks, cups, or ounces.
- Leave the “Show % Daily Value” box checked if you want the result expressed as a percentage of the 4,700 mg adult Daily Value.
- Press Calculate Potassium to see the milligram total and a short step-by-step breakdown.
Formula and Conversion Basics
According to USDA FoodData Central, regular salted and unsalted butter both provide roughly 24 mg of potassium per 100 grams. That works out to 0.24 mg of potassium per gram, which is the reference value used in this calculator.
Potassium (mg) = grams of butter × 0.24
If your measurement is in a volume unit, the calculator first converts it to grams using these standard weights:
- 1 teaspoon = 4.73 g
- 1 tablespoon = 14.2 g
- 1 US stick = 8 tablespoons = 113.4 g
- 1 cup = 2 sticks = 227 g
- 1 ounce = 28.35 g
For the most accurate log, weigh butter on a food scale rather than relying on volume, especially if you are measuring for a therapeutic kidney diet.
Worked Examples
Example 1: One tablespoon. A standard US tablespoon of butter weighs about 14.2 g. Potassium = 14.2 × 0.24 = 3.4 mg. This is less than 0.1% of the daily value, so butter is effectively negligible for potassium counting.
Example 2: Half a stick. Half a stick of butter is 4 tablespoons, or about 56.7 g. Potassium = 56.7 × 0.24 = 13.6 mg.
Example 3: 100 grams of butter. At 24 mg per 100 g, a 100 g portion supplies exactly 24 mg of potassium. By comparison, a medium banana has about 422 mg, so 100 g of butter contains only about 5.7% as much potassium as that banana.
Reference Table: Potassium in Common Butter Servings
Approximate values based on 24 mg potassium per 100 g butter.
| Serving | Weight | Potassium |
|---|---|---|
| 1 teaspoon | 4.7 g | 1.1 mg |
| 1 tablespoon | 14.2 g | 3.4 mg |
| 2 tablespoons | 28.4 g | 6.8 mg |
| 1/4 cup (4 tbsp) | 56.7 g | 13.6 mg |
| 1/2 cup (1 stick) | 113.4 g | 27.2 mg |
| 1 cup | 227 g | 54.5 mg |
| 100 g | 100 g | 24 mg |
Rounded to one decimal place. Stick and cup values use the US standard stick size.
Tips for Low-Potassium Meal Planning
Whipped butter contains more air, so a tablespoon weighs less and delivers somewhat less potassium per spoonful. That is favorable for potassium restriction, but recipes that are sensitive to fat or moisture may behave differently if you swap in whipped butter, so measure by weight for cooking.
Butter is genuinely useful on a low-potassium diet because it adds calories and fat without meaningful potassium. However, it is high in saturated fat and often salt, so portion control still matters. Keep a food diary and combine individual foods to see your whole-day potassium. If you also track other foods, try the bacon potassium calculator or yogurt potassium calculator to build a complete nutrient picture.
Frequently Asked Questions
Is salted or unsalted butter lower in potassium? Neither. Both regular salted and unsalted butter contain about 24 mg per 100 g. Salted butter contains more sodium, but the potassium content is essentially the same.
Is butter allowed on a low-potassium kidney diet? In moderate amounts, butter is generally considered a low-potassium food and is often allowed on renal diets. Still, it contributes saturated fat, and salted butter adds sodium, so always follow the individualized plan from your nephrologist or renal dietitian.
Does cooking change the potassium content of butter? Not meaningfully. Butter is not boiled and drained like vegetables; it is incorporated into dishes or used as a cooking fat, so the small amount of potassium remains with the food. Baking, sautéing, or roasting does not remove potassium from butter.
Why is butter so low in potassium? Potassium is water-soluble, and butter is mostly milk fat. The potassium dissolved in milk stays largely in the aqueous buttermilk or whey rather than in the butterfat. For a deeper look at potassium in the diet, see the NIH Office of Dietary Supplements Potassium fact sheet.