Beans and legumes are nutritional powerhouses — packed with plant protein, fiber, and micronutrients — but they can be surprisingly carb-dense. If you’re tracking macronutrients, following a low-carb or keto-style diet, or simply trying to budget your daily carbohydrate intake, you need to know how many net carbs you’re actually eating. Standard nutrition labels list total carbohydrates, which include dietary fiber that your body doesn’t fully digest. This calculator separates the two instantly.
Pick your bean type, enter your serving size in grams, cups, or ounces, and the calculator returns total carbohydrates, dietary fiber, net carbs for that serving, and the net carb count per 100 grams. It covers eight common varieties — black beans, kidney beans, pinto beans, navy beans, chickpeas, lentils, edamame, and green beans — using standard USDA nutrition data for cooked beans.
Whether you’re meal-prepping, building a plant-based plate, or just curious how beans fit into your carb budget, this tool gives you a clear, fast answer every time.
🥫 Beans Net Carbs Calculator
Work out net carbs for cooked beans and legumes in seconds.
Step-by-Step Guide
Using the Beans Net Carbs Calculator takes less than ten seconds:
- Choose your bean or legume from the dropdown. The values reflect boiled, cooked beans with no added salt, fat, or sugar — the form you'd typically add to soups, salads, and chili.
- Enter a serving size in the number field, then pick the matching unit: grams, cups, or ounces. Not sure what a serving looks like? Use the quick preset buttons — ½ cup, 1 cup, or 100 g — to fill in the amount instantly.
- Click Calculate Net Carbs. You'll see total carbs, dietary fiber, and net carbs for your exact serving, plus the net carb value per 100 g so you can compare bean varieties at a glance.
- Hit Reset to clear the form and start a fresh calculation.
How Net Carbs Are Calculated
The standard net carbohydrate formula is:
Beans and legumes contain negligible sugar alcohols, so the formula simplifies to Net Carbs = Total Carbs − Fiber. Fiber is subtracted because it's a carbohydrate that resists digestion — instead of being broken down into glucose and absorbed into the bloodstream, it passes through the digestive tract largely intact. That means fiber doesn't raise blood sugar the way digestible carbs do, which is exactly why low-carb eaters track net carbs rather than total carbs.
The calculator scales USDA nutrient values per 100 grams of cooked beans to your serving size:
Fiber is scaled the same way, then subtracted.
Values are drawn from the USDA FoodData Central database, the standard public reference behind most nutrition labels. You can explore the full dataset at fdc.nal.usda.gov.
Worked Examples
Example 1 — 1 cup of cooked black beans. A cup of cooked black beans weighs about 172 g. Total carbs: 23.7 × 1.72 = 40.8 g. Fiber: 8.7 × 1.72 = 15.0 g. Net carbs: 40.8 − 15.0 = 25.8 g.
Example 2 — 100 g of cooked lentils. Lentils are one of the lower-carb options in the legume family. Total carbs: 20.1 g. Fiber: 7.9 g. Net carbs: 20.1 − 7.9 = 12.2 g.
Example 3 — 3 oz of shelled edamame. Three ounces equals roughly 85 g. Total carbs: 8.9 × 0.85 = 7.6 g. Fiber: 5.2 × 0.85 = 4.4 g. Net carbs: 7.6 − 4.4 = 3.2 g — small enough to fit even a strict keto day.
Net Carbs by Bean Type
Per 100 g of cooked beans (approximate USDA values):
| Bean / Legume | Total Carbs (g) | Fiber (g) | Net Carbs (g) |
|---|---|---|---|
| Green beans | 7.1 | 3.4 | 3.7 |
| Edamame | 8.9 | 5.2 | 3.7 |
| Lentils | 20.1 | 7.9 | 12.2 |
| Black beans | 23.7 | 8.7 | 15.0 |
| Kidney beans | 22.8 | 7.4 | 15.4 |
| Navy beans | 26.1 | 10.5 | 15.6 |
| Pinto beans | 26.2 | 8.9 | 17.3 |
| Chickpeas | 27.4 | 7.6 | 19.8 |
For a deeper look at how much fiber each legume delivers, see the bean fiber calculator — fiber is the main reason beans are so filling and so friendly to blood sugar.
Tips for Low-Carb Bean Lovers
- Watch portion size. The difference between ½ cup and 1 cup of black beans is roughly 13 g of net carbs — enough to blow a modest daily budget.
- Choose green beans or edamame when you want the bean feel with a fraction of the carbs. Both sit around 3–4 g net carbs per 100 g.
- Weigh cooked, not dry. Dried beans roughly triple in weight when cooked, so a 50 g dry portion becomes about 150 g cooked. Logging dry weight as cooked weight is a classic tracking mistake.
- Rinse canned beans. Rinsing doesn't meaningfully change the carb count, but it washes away a good portion of the added sodium.
- Pair beans with protein or fat. Eating them with eggs, olive oil, or meat slows digestion and blunts the blood-sugar response.
Frequently Asked Questions
Why do different apps show different net carb numbers for the same bean?
Sources disagree for a few reasons: some report raw beans, others report cooked; some use rounded label values; and databases vary in how they classify fiber components. This calculator uses cooked, boiled values from USDA FoodData Central, the most reliable public reference.
Do canned beans have the same net carbs as home-cooked beans?
Very close. Commercial canning is similar to boiling, so total and net carbs are nearly identical. The main difference is sodium, which doesn't affect carb counts. If the can's label shows different numbers, trust the label over any generic database.
Are beans allowed on a keto diet?
Strict keto (under 20 g net carbs per day) leaves little room for most beans beyond a small handful of green beans or edamame. More liberal low-carb plans — 50–100 g daily — can easily accommodate a half-cup portion of lentils or black beans.
Does soaking or sprouting beans reduce net carbs?
Sprouting and extended soaking can slightly reduce some fermentable sugars and improve mineral absorption, but the effect on total net carbs is minor. Don't rely on it as a carb-reduction strategy.