Mushrooms are a favorite for low-carb and keto dieters, but their carbohydrate content varies significantly by variety and preparation. This calculator lets you quickly find the total carbs, net carbs, and fiber for any amount of mushrooms, standardized to a 100g reference. Whether you're tracking macros, planning a meal, or just curious about your favorite fungi, this tool gives you accurate, per-100g values.
Simply choose the mushroom type, enter the weight you plan to eat, and optionally adjust for cooking method (raw vs. cooked) to see how water loss concentrates carbs. The calculator also breaks down net carbs (total carbs minus fiber) — the number most relevant for blood sugar and ketosis. Perfect for nutritionists, fitness enthusiasts, and anyone following a low-carb lifestyle.
🍄 Mushroom Carb Calculator
📊 Results
Step-by-step:
How to Use This Tool
Select your mushroom variety from the dropdown, enter the weight you plan to eat (in grams, ounces, or pounds), and choose the preparation method — raw, cooked (boiled/drained), or grilled. The calculator instantly shows total carbs, fiber, and net carbs for your portion, plus the per-100g total carb value. Use the quick-fill buttons to test common serving sizes.
For accurate tracking, weigh mushrooms in their raw state before cooking. If you only have cooked weight, you can still use the calculator by selecting the appropriate preparation — the tool applies a factor to approximate the concentration effect of water loss.
How It Works
The calculator uses USDA FoodData Central values for each mushroom variety, expressed per 100 grams. For raw mushrooms, the values are direct. For cooked or grilled mushrooms, we apply a concentration factor to account for water loss during cooking — typically 1.5x for boiled/drained and 1.3x for grilled. This is an approximation; actual values depend on cooking time and method.
Net carbs are calculated as total carbs minus fiber. Fiber is indigestible and doesn't raise blood sugar, so net carbs are the key number for keto and low-carb diets.
Worked Examples
Example 1: 150 g raw white mushrooms. Total carbs = 3.3 × 150/100 = 4.95 g. Fiber = 1.0 × 150/100 = 1.5 g. Net carbs = 4.95 − 1.5 = 3.45 g.
Example 2: 200 g cooked shiitake (boiled). Base total = 6.8 g/100g, factor 1.5 → 10.2 g/100g. Total carbs = 10.2 × 200/100 = 20.4 g. Fiber = 2.5 × 1.5 × 200/100 = 7.5 g. Net carbs = 12.9 g.
Tips & Best Practices
- Always weigh mushrooms raw for the most accurate macro count, as water content changes dramatically with cooking.
- If you're tracking net carbs for keto, remember that fiber is subtracted — mushrooms are excellent low-net-carb vegetables.
- Different varieties have different carb profiles; shiitake and enoki are higher in carbs than white or portobello.
- Use the per-100g value to compare mushrooms with other vegetables in your meal plan.
Factors Affecting Accuracy
Carb values can vary slightly by growing conditions, maturity, and storage. The data here is based on USDA standard references, which are reliable for general tracking. Cooking method significantly affects water content — boiling leaches some water-soluble nutrients, while grilling removes moisture more aggressively. Our factors are estimates; for precise medical or clinical use, consult a registered dietitian.
Frequently Asked Questions
Are mushrooms keto-friendly?
Yes, most mushrooms are very low in net carbs. For example, 100g of raw white mushrooms has only about 2.3g net carbs, making them a staple in ketogenic diets.
Do cooked mushrooms have more carbs?
By weight, yes — because cooking removes water, the same weight of cooked mushrooms contains more dry matter, including carbs. But the actual carb content of the mushroom doesn't change; it's just concentrated.
What is the difference between total carbs and net carbs?
Total carbs include all carbohydrates, including fiber. Net carbs subtract fiber because fiber isn't digested and doesn't affect blood sugar. For low-carb diets, net carbs are the more relevant number.
Reference Data
| Variety | Total Carbs (g/100g) | Fiber (g/100g) | Net Carbs (g/100g) |
|---|---|---|---|
| White / Button | 3.3 | 1.0 | 2.3 |
| Cremini | 4.3 | 0.6 | 3.7 |
| Portobello | 3.9 | 1.3 | 2.6 |
| Shiitake | 6.8 | 2.5 | 4.3 |
| Oyster | 6.1 | 2.3 | 3.8 |
| Enoki | 7.8 | 2.7 | 5.1 |
| Maitake | 7.0 | 2.7 | 4.3 |
| Morel | 5.1 | 2.8 | 2.3 |
Data source: USDA FoodData Central. For more detailed nutritional information, visit the USDA FoodData Central.