Mushrooms are famous for being low in calories and almost fat-free, but 'almost' still matters when you are counting macros or building a precise meal plan. A large pile of mushrooms can contain a gram or two of fat, especially if you choose shiitake or morels. This calculator converts fat per 100g for seven common mushroom varieties into the actual fat in your portion — no spreadsheet guesswork.
Select a variety, enter the amount in grams, ounces, or kilograms, and split the batch into servings if you like. The tool instantly shows total fat, fat per 100g, and fat per serving, plus the percentage of the daily reference value for a 2,000-calorie diet. It's useful for meal preppers, keto and low-fat eaters, calorie counters, and anyone curious about whole-food nutrition.
The fat values are based on raw mushrooms from USDA nutrient data. For cooked mushrooms, the mushroom's own fat stays about the same, but any oil or butter in the pan will add extra fat that this tool does not include.
Mushroom Fat Per 100g Calculator
How to Use This Tool
This calculator is designed for anyone who wants a quick, reliable fat estimate from a mushroom portion. Start by selecting the closest variety from the dropdown. If you are using a mix of mushrooms, choose the variety that dominates the dish, or use the highest-fat one to stay conservative.
- Choose the mushroom variety that matches your meal.
- Enter the total weight of the mushrooms. You can use grams, ounces, or kilograms.
- Set the number of servings if the batch will be divided, otherwise leave it at 1.
- Click Calculate to see total fat, fat per 100g, fat per serving, and the percent of the daily reference value.
Fat Values Behind the Calculator
The calculator uses fat values for raw mushrooms from representative USDA nutrient data. Different databases can vary slightly because mushrooms are natural products, but these figures are close for fresh, raw mushrooms.
| Variety | Fat per 100g (raw) | Notes |
|---|---|---|
| White button | 0.34 g | Light, mild, most common mushroom |
| Cremini / brown | 0.14 g | Slightly firmer and earthier than white button |
| Portobello | 0.24 g | Large caps with a meaty texture |
| Shiitake | 0.49 g | Rich umami, commonly used in stir-fries |
| Oyster | 0.41 g | Delicate, fan-shaped, cooks quickly |
| Enoki | 0.29 g | Thin and crunchy, often used in soups |
| Morel | 0.57 g | Wild mushroom with a honeycomb cap |
These values are per 100g of fresh, raw mushrooms. Cooking mushrooms in water or dry heat does not remove their intrinsic fat; the number stays essentially the same after accounting for moisture loss. The main source of added fat is what you put in the pan. For a deeper look at nutrient data, the USDA FoodData Central is a reliable reference.
Why Mushroom Fat Matters in Diet Planning
Mushrooms are a low-fat, high-volume food, which makes them valuable for weight management and for filling out meals without blowing your daily fat targets. One hundred grams of white button mushrooms contains only about 0.34g fat — far less than the fat found in nuts, cheese, oils, or fatty meats. Yet mushrooms are often served in generous portions, and the serving size matters more than you might think.
For meal preppers and macro counters, the difference between 0.3g and 0.6g from mushrooms is tiny, but it is still part of a complete dietary record. This tool is especially handy for low-fat and plant-forward eating plans, volume eaters, and people who track every gram of total fat for medical or performance reasons.
Worked Examples
Example 1: Oyster mushrooms for dinner. You weigh out 150g of fresh oyster mushrooms and plan to divide them between two plates. Oyster mushrooms contain 0.41g fat per 100g. Total fat = (150 ÷ 100) × 0.41 = 0.62g. Per serving = 0.62 ÷ 2 = 0.31g.
Example 2: White button mushrooms in ounces. A recipe calls for 8 oz of white button mushrooms. First convert: 8 oz = 226.8g. The fat per 100g is 0.34g, so total fat = 2.268 × 0.34 = 0.77g. Split into 4 servings gives about 0.19g per serving.
Example 3: Portobello stir-fry. A vegetarian stir-fry uses 300g of portobello caps across 3 servings. Portobello has 0.24g fat per 100g, so total fat = (300 ÷ 100) × 0.24 = 0.72g. Each serving contains 0.24g fat.
Factors Affecting Accuracy
Fresh mushrooms are natural products, so fat can vary slightly with growing conditions, maturity, and cultivar. Dried mushrooms are a different story: removing water concentrates all nutrients, including fat, so the per-100g number can be several times higher. This tool is designed for fresh, raw mushrooms, not dried or rehydrated products.
If you cook mushrooms in oil, butter, or other fat, that added fat is not included. Sliced mushrooms can soak up oil quickly, so the total fat in the finished dish may be much higher than the mushroom's intrinsic fat. The calculator gives you the mushroom contribution only.
Frequently Asked Questions
Are mushrooms fat-free?
No food is truly fat-free. Most raw mushrooms contain between 0.1 and 0.6g of fat per 100g, which is negligible in a balanced diet but not zero.
Do canned or jarred mushrooms have the same fat?
Canned mushrooms are usually close in natural fat, but some are packed in oil or include added fats, and many have added sodium. Check the nutrition label rather than relying on raw values.
Does cooking change the fat content?
The mushroom's own fat stays almost unchanged, but moisture loss makes the fat appear higher per 100g in cooked mushrooms. Added oil and butter are usually the main source of fat in cooked mushroom dishes.
Why use per 100g values?
Food labels and nutrition databases report per 100g as a standard, so you can compare mushrooms with vegetables, grains, and legumes on an equal basis. It also makes the math simple: if you eat 225g, multiply the per-100g value by 2.25.
If you'd like to compare fat in another low-fat produce item, our pea fat calculator does the same kind of calculation for green peas.