Lentils are an affordable, fiber-rich staple, but their carbohydrate content changes dramatically depending on whether you weigh them dry or cooked. This calculator estimates the total carbs, fiber, and net carbs in any portion of lentils, then normalizes the numbers to a 100 g reference so results are easy to compare and scale. It is useful for macro tracking, low-carb or diabetic meal planning, and anyone who wants a quick, reliable answer in the kitchen.
Choose your lentil type (brown, red, French/Puy, or black), select raw or cooked preparation, and enter the amount in grams, kilograms, or ounces. The calculator applies standard nutrition data per 100 g and shows a clear step-by-step breakdown, so you can verify each number or adapt it to other serving sizes.
🥘 Enter Your Lentil Details
How to Use This Tool
Start by selecting the lentil variety you're working with — brown or green, red or split, French (Puy), or black (Beluga) — then choose whether your measurement is for raw, dry lentils or boiled, drained ones. These two choices matter more than the portion size, because cooking roughly triples the weight of lentils while leaving their total carbohydrate content essentially unchanged. Enter the portion in grams, kilograms, or ounces, or tap one of the quick-amount buttons to fill 50, 100, 150, or 200 g. The calculator converts the portion to grams, applies the selected nutrient values per 100 g, and returns total carbs, fiber, and net carbs in a single step.
How the Calculation Works
Each lentil type has a reference value for total carbohydrate and dietary fiber per 100 g, drawn primarily from USDA FoodData Central for whole and split lentils. The calculator first converts your entered amount into grams — 1 kg = 1000 g and 1 oz = 28.3495 g — then divides by 100 to get a scale factor, and finally multiplies the per-100 g values by that factor:
scale factor = portion in grams ÷ 100
total carbs = carbs per 100 g × scale factor
fiber = fiber per 100 g × scale factor
net carbs = total carbs − fiber
Net carbs are shown only because many low-carb and diabetic meal plans subtract insoluble fiber, since it isn't digested into glucose. The checkbox lets you hide that line if you prefer to track total carbohydrate instead.
Worked Examples
Running the same meal through raw and cooked entries highlights how much the per-100 g numbers change:
Unit conversion is built into the same step. If your recipe lists 6 oz of cooked Puy lentils, the tool converts 6 oz to 170.1 g, applies the cooked Puy values (19.1 g carbs, 7.2 g fiber), and reports about 32.5 g total carbs and 12.2 g net carbs. You can use this to scale any recipe printed in ounces or to build a custom serving size for a meal-prep container.
Reference Values per 100 g
The table below lists the values used by the calculator for each variety. All are rounded to one decimal for readability; the calculator itself uses these rounded values so your results match the table.
| Type | Carbs raw | Fiber raw | Carbs cooked | Fiber cooked |
|---|---|---|---|---|
| Brown / Green | 63.4 g | 10.7 g | 20.1 g | 7.9 g |
| Red / Split | 62.9 g | 10.6 g | 19.5 g | 7.6 g |
| French / Puy | 60.8 g | 10.1 g | 19.1 g | 7.2 g |
| Black / Beluga | 60.3 g | 10.0 g | 19.0 g | 7.0 g |
Values are aggregated from USDA FoodData Central entries for raw and boiled lentils. Actual values vary by crop year, brand, and cooking time.
Factors Affecting Accuracy
Cooked-lentil values assume lentils boiled in water without added fat, sugar, or salt, then drained. Cooking time changes water absorption: a longer simmer means more water weight and slightly lower carbs per 100 g, even though the total carbs in the pot stay the same. Adding stock, oil, or sauces will dilute or raise the numbers accordingly. Varietal differences are real but modest — red split lentils typically have a touch less fiber than whole brown varieties. If you rely on a specific brand's package, its label may differ by a few percent from USDA figures, and you can use this tool's numbers as a consistent baseline.
Common Mistakes to Avoid
- Weighing dry lentils but using the cooked column — you'll undercount by roughly a factor of three.
- Using net carbs without checking whether your diet subtracts all fiber or only insoluble fiber; European labels and some apps already list a "net carb" figure that differs.
- Estimating by cups: a cup of cooked lentils varies with how densely it's packed; a gram scale removes the guesswork.
- Forgetting that soaking water is discarded — always weigh dry lentils before soaking if you plan to use the raw column.
Frequently Asked Questions
Are lentils considered high-carb? Compared with non-starchy vegetables, yes — a 100 g serving of cooked lentils carries about 20 g of total carbs. But because roughly 40% of that is dietary fiber, the net carb impact is closer to 12 g, and the protein plus fiber slows digestion. Many diabetic and low-glycemic meal plans include lentils in moderation.
Why do the cooked numbers look so much lower than raw? Boiling adds water, so 100 g of cooked lentils contains fewer lentil solids than 100 g of raw ones. The total carbs in your pot don't change when you cook — only the concentration per gram of final weight changes. That's why matching the measurement state to the database entry matters.
Can I rely on these numbers for meal prep? They're a solid estimate for whole lentils cooked at home. For packaged lentil products (pouches, canned soups, ready meals), read the label's serving size and use the label values instead, because added ingredients change the carb count.
Where does the data come from? The reference values are adapted from USDA FoodData Central. You can look up official entries at FoodData Central, and the Wikipedia article on lentils offers a useful overview of varieties and culinary uses.