The Mushroom Potassium Calculator estimates how much potassium is in your serving of mushrooms in seconds. Choose a variety such as white button, cremini, portobello, shiitake, oyster, enoki, maitake, or morel, then enter the amount in grams, ounces, or cups. The tool returns total milligrams and the percentage of the FDA Daily Value.
Potassium figures are based on average nutrient profiles for raw mushrooms from USDA FoodData Central. Different varieties have very different potassium densities: cremini supplies roughly 448 mg per 100 g, while maitake supplies around 204 mg per 100 g. Selecting the correct variety is therefore essential for a useful estimate.
Dietitians, home cooks, and athletes can use the results for micronutrient tracking, kidney-conscious meal planning, portion comparison, and post-training recovery. A step-by-step breakdown makes it easy to see exactly how each total was calculated.
🍄 Mushroom Potassium Calculator
Raw averages, quick estimates.
📊 Calculation breakdown
- Serving weight—
- Potassium per 100 g—
- Potassium in serving—
- Daily Value—
Quick Start Guide
- Pick a mushroom variety from the dropdown — white button, cremini, portobello, shiitake, oyster, enoki, maitake, or morel. The potassium density readout updates instantly, so you can compare varieties before you even type a serving size.
- Enter your serving size in grams, ounces, or cups of raw chopped mushrooms. Use the number field together with the unit dropdown, or tap a preset pill such as 100 g, 70 g, 1 cup, or 3 oz to fill both fields in one click.
- Decide whether to show the Percent Daily Value. The FDA reference target for potassium is 4,700 mg per day, and the checkbox toggles that percentage on or off in both the main result card and the step-by-step breakdown.
- Click “Calculate potassium” to see your total in milligrams, the percentage of the Daily Value, and a full breakdown showing the serving weight in grams, the density used, and how the final figure was derived.
- Use Reset to clear everything and start over, or simply change the serving size and recalculate to compare portions side by side.
How the Calculation Works
Potassium densities come from average nutrient profiles for raw mushrooms in USDA FoodData Central. The core formula is simple: potassium in mg = serving weight in grams ÷ 100 × potassium per 100 g.
Unit conversions happen before the formula runs. One ounce equals 28.3495 grams, and a standard cup of raw chopped mushrooms is approximated at 70 grams. For example, 3 oz becomes 85.0 g, then 85.0 ÷ 100 × 420 = 357 mg for oyster mushrooms.
Worked Examples
Example 1 — Cremini, 3 oz serving. Convert ounces to grams: 3 × 28.3495 = 85.0 g. Cremini density is 448 mg per 100 g. So potassium = 85.0 ÷ 100 × 448 = 381 mg, which is about 8.1% of the 4,700 mg Daily Value.
Example 2 — Portobello, 1 cup chopped. Convert cups to grams: 1 × 70 = 70 g. Portobello density is 364 mg per 100 g. So potassium = 70 ÷ 100 × 364 = 255 mg, about 5.4% of the Daily Value. Double the serving to 2 cups and the total becomes 510 mg, roughly 10.9% — a handy trick for quick portion comparisons.
Potassium Reference Table
Average potassium per 100 g for common raw mushroom varieties, sorted from highest to lowest density:
| Variety | Potassium (mg per 100 g) |
|---|---|
| Cremini (brown) | 448 |
| Oyster | 420 |
| Morel | 411 |
| Portobello | 364 |
| Enoki | 359 |
| White button | 318 |
| Shiitake | 304 |
| Maitake | 204 |
These are raw averages. Cooked mushrooms weigh less because water evaporates, so a 100 g portion of cooked mushrooms contains more potassium than 100 g raw. If you track cooked portions, use the lower cooked weight — for example, 100 g of raw white button mushrooms typically shrinks to roughly 80–90 g when sautéed.
Tips & Best Practices
- Weigh mushrooms raw whenever possible. Volume estimates like cups are convenient, but a gram scale is far more consistent for tracking.
- Treat the Daily Value percentage as a rough benchmark, not a personal medical target. Your needs depend on age, activity level, and any underlying health conditions.
- Compare varieties at the same weight. A 100 g serving of cremini delivers about 448 mg, while 100 g of maitake gives only 204 mg — a difference of more than 2× with no change in portion size.
- For kidney-conscious meal planning, remember that potassium from mushrooms adds to potassium from potatoes, bananas, beans, tomatoes, and other foods in the same meal. Track the whole plate, not just one ingredient.
Factors Affecting Accuracy
Every estimate carries natural variability. Potassium in mushrooms shifts with growing substrate, compost chemistry, maturity at harvest, and storage time. The USDA values used here are averages across multiple samples and remain the best publicly available reference, but a specific batch could differ by 10–20%.
Preparation also changes the picture. Boiling can leach some potassium into the cooking water, while roasting and sautéing concentrate minerals by driving off moisture. Dried mushrooms are a separate case: they rehydrate with water, so their weight and potassium density change dramatically before and after soaking.
Frequently Asked Questions
Are raw and cooked mushrooms different in potassium?
Cooking does not destroy potassium, but it changes weight as water is lost. A 100 g portion of cooked mushrooms therefore delivers more potassium than 100 g raw. This calculator assumes raw mushrooms.
Why is the Daily Value 4,700 mg?
That figure is the FDA reference used on Nutrition Facts labels, based on intake levels associated with healthy blood pressure. Your personal target may differ — follow your healthcare provider's advice.
Can I use this for kidney-friendly meal planning?
Yes, as a starting estimate — but potassium varies by brand, growing conditions, and cooking method. If you are on a restricted-potassium diet, confirm portion sizes with your dietitian or doctor.
What about canned or dried mushrooms?
Canned mushrooms are packed in water and can have lower potassium per 100 g because some minerals leach into the liquid. Dried mushrooms are the opposite — highly concentrated until rehydrated. This calculator reflects raw fresh mushrooms only.
For authoritative background on potassium in the diet, see the NIH Office of Dietary Supplements Potassium Fact Sheet.