Net Carbs Calculator

Net carbs are the carbohydrates that your body actually digests and absorbs. They are calculated by subtracting dietary fiber and (partially) sugar alcohols from total carbohydrates, since fiber passes through the digestive system largely unabsorbed and sugar alcohols have a reduced glycemic impact. The FDA does not officially recognize the term, but it is widely used in low-carb and keto communities.

The standard formula is: Net Carbs = Total Carbohydrates − Fiber − (Sugar Alcohols ÷ 2). For whole foods with no added sugar alcohols, you simply subtract the fiber. For processed or packaged foods listing sugar alcohols, you divide that amount by two before subtracting, since they are only partially absorbed.

Different sugar alcohols are absorbed at different rates. Erythritol is almost entirely excreted without being metabolized, so most approaches subtract it fully. Maltitol, on the other hand, has a significant glycemic impact and should only be partially subtracted. Using the wrong divisor can overestimate how 'keto-friendly' a product is.

For a strict ketogenic diet, most guidelines suggest staying under 20–50 g of net carbs per day to maintain ketosis. A general low-carb diet may allow 50–130 g per day. Individual tolerance varies, so it is best to start conservative and adjust based on your body's response and any advice from a healthcare professional.

Tracking net carbs gives a more accurate picture of a food's actual impact on blood sugar and insulin. Fiber-rich foods may look high in total carbs but have a very low glycemic effect. For people managing diabetes, following keto, or doing low-carb dieting, net carbs are a more meaningful metric than total carbohydrates alone.

The ketogenic diet restricts carbohydrate intake to force the body into ketosis — a metabolic state where fat is burned as the primary fuel. Since fiber and most sugar alcohols do not raise blood sugar or prevent ketosis, keto dieters subtract them from total carbs to get net carbs, allowing a wider variety of high-fiber vegetables and low-sugar-alcohol treats within their daily limit.

Whole, unprocessed foods (like vegetables, fruits, and legumes) naturally contain very little to no sugar alcohols. For those foods, you only need to subtract dietary fiber from total carbs. Sugar alcohol deductions become relevant mainly with processed, packaged, or 'low-carb' labeled products that use sweeteners like erythritol, xylitol, or maltitol.

Yes. In the United States, fiber is listed separately under Total Carbohydrates, so you subtract it manually. In some European countries, nutrition labels already list carbohydrates excluding fiber (sometimes labeled 'carbohydrates of which sugars'), meaning the net carbs may already be accounted for. Always check your local label format before applying the formula.