Protein and potassium often appear on the same food label but are rarely planned together, even though both matter for muscle maintenance, blood pressure regulation, and everyday energy. This calculator estimates both nutrients for any portion of the food you eat. Pick from a built-in library of common protein sources and potassium-rich produce, enter your portion size in grams or ounces, and instantly see protein, potassium, and each nutrient's share of the daily value.
Need something outside the list? Enter custom protein and potassium values per 100 g from any nutrition label or database, and the tool uses those instead. The step-by-step breakdown shows the math behind every result, making it easy to verify, adjust portions, and compare foods side by side. It is equally useful for meal planning, muscle-building diets, blood pressure management, and kidney-conscious eating.
How to Use This Tool
Start by choosing a food from the dropdown menu. The built-in list covers common protein sources such as chicken breast, salmon, lean beef, tofu, lentils, and Greek yogurt, as well as potassium-rich produce including spinach, sweet potato, avocado, and banana. If the food you want is not listed, switch to custom mode by entering its protein and potassium values per 100 g — you will find exactly these numbers on any Nutrition Facts label that reports per 100 g, or in a food database.
Next, type your portion size and choose the unit (grams or ounces). Press Calculate to see the protein and potassium content of your portion plus each nutrient's percentage of the daily value. A step-by-step breakdown below the results walks through the math, so you can verify the numbers or adjust the portion until it fits your meal plan.
How the Calculator Works
The calculator uses per-100-gram nutrient values, the standard format used by the USDA FoodData Central database and most international food labels. Once a food is selected, the tool applies a simple ratio:
Potassium: (potassium per 100 g × portion weight in g) ÷ 100
Daily values are based on the FDA's reference amounts for general nutrition advice: 50 g of protein and 4,700 mg of potassium per day. Percent DV is calculated as your result divided by the reference amount, multiplied by 100. This matches the math used on Nutrition Facts labels in the United States, as described in the FDA's Daily Value guidance.
Worked Examples
Example A — Chicken breast, 150 g. Cooked chicken breast contains roughly 31 g of protein and 390 mg of potassium per 100 g. For a 150 g portion: protein = (31 × 150) ÷ 100 = 46.5 g, which is 93% of the 50 g daily value. Potassium = (390 × 150) ÷ 100 = 585 mg, which is 12% of the 4,700 mg daily value.
Comparing these two examples highlights why planning both nutrients together matters: a high-protein meal can be modest in potassium, while a potassium powerhouse can deliver very little protein.
Reference Table: Protein & Potassium in Common Foods
Values below are approximate and based on typical USDA reference values for common preparations. Always verify against the specific product label when precision matters.
| Food | Protein (g / 100 g) | Potassium (mg / 100 g) |
|---|---|---|
| Chicken breast (cooked) | 31 | 390 |
| Canned tuna (drained) | 29 | 250 |
| Lean beef (cooked) | 26 | 350 |
| Peanut butter | 25 | 558 |
| Tofu (firm) | 15.5 | 120 |
| Greek yogurt (nonfat) | 10 | 150 |
| Lentils (cooked) | 9 | 370 |
| Spinach (cooked) | 3 | 470 |
| Sweet potato (baked) | 2 | 475 |
| Banana | 1.1 | 358 |
| Baked potato | 2.5 | 535 |
| Almonds | 21.2 | 733 |
Tips & Best Practices
- Stay consistent with raw vs cooked weights. Meat and seafood lose water during cooking, so nutrient values per 100 g differ between raw and cooked forms.
- Boiling can leach potassium into the cooking water. Steaming, roasting, or sautéing helps retain more of the mineral.
- For kidney-friendly or potassium-restricted meal plans, follow the target set by your doctor or dietitian — many renal guidelines recommend far lower daily potassium limits than the general 4,700 mg reference.
- Pair this calculator with a kitchen scale for the most accurate portions, especially for calorie-dense foods like nuts and peanut butter.
Frequently Asked Questions
Why does the calculator show a daily value for potassium? The FDA uses 4,700 mg per day as the reference for potassium on Nutrition Facts labels. The percent DV helps you judge how one serving contributes to a daily diet. Individuals with kidney conditions should use the potassium target prescribed by their healthcare provider instead.
Can I trust the built-in food values? The numbers are typical values drawn from USDA reference data, but real foods vary by brand, cut, ripeness, and cooking method. For packaged foods, use the custom fields with values from the package label — that gives you results specific to the exact product you are eating.
Why does protein percent DV look different from what I expected? The calculator uses the FDA's 50 g reference for labeling. Personal protein needs depend on body weight, activity level, and health goals; athletes and older adults often need more. The 50 g reference is used so results match standard label math.
What counts as high potassium? As a rough guideline, foods providing 20% or more of the daily value per serving (i.e., roughly 940 mg or more) are considered high in potassium. Use the results to spot which foods move the needle.
Further Reading
For more detailed nutrient information, explore the USDA FoodData Central database. For guidance on daily values, see the FDA's Daily Value guidance, and for potassium science and intake recommendations, the National Institutes of Health Potassium Fact Sheet for Health Professionals is a reliable resource.