Net Carbs Calculator

Net carbs are the carbohydrates your body actually digests and absorbs, affecting blood sugar levels. They are calculated by subtracting dietary fiber and a portion of sugar alcohols from total carbohydrates. Fiber passes through the digestive system without being absorbed, while many sugar alcohols are only partially metabolized.

The basic formula is: Net Carbs = Total Carbohydrates − Fiber − (Sugar Alcohols × impact factor). The impact factor depends on the type of sugar alcohol — erythritol is counted as zero, maltitol is counted fully, and most others are counted at half value. Use this calculator to apply the right factor automatically.

Tracking net carbs is essential for low-carb and ketogenic diets, where the goal is to keep carbohydrate intake low enough to maintain a metabolic state called ketosis. Net carbs give a more accurate picture of how a food affects your blood sugar compared to total carbs alone.

For a ketogenic diet, most people aim for fewer than 20–50g of net carbs per day. A general low-carb diet may allow 50–150g per day. Your ideal target depends on your goals, activity level, and individual metabolism — consult a healthcare professional for personalized guidance.

Not all sugar alcohols affect blood sugar equally. Erythritol and allulose are almost entirely excreted without absorption, so they don't count toward net carbs. Maltitol has a significant glycemic impact and should be counted in full. Most other sugar alcohols (like xylitol and sorbitol) fall somewhere in between and are typically counted at half value.

US nutrition labels typically list total carbohydrates and fiber as separate line items, with fiber sometimes already excluded from the total. EU labels include fiber within the total carbohydrate figure. Selecting the correct labeling standard ensures fiber isn't subtracted twice or not at all.

The ketogenic diet restricts carbohydrate intake dramatically, forcing the body to burn fat for fuel instead of glucose. This metabolic state — ketosis — can promote fat loss and improve insulin sensitivity. By tracking net carbs rather than total carbs, followers of keto can include fiber-rich foods without jeopardizing ketosis.

Essentially, yes — net carbs represent the carbohydrates your body can digest and convert to glucose. Fiber is indigestible and passes through largely intact. Sugar alcohols are partially absorbed depending on their type. The net carb count reflects the realistic metabolic load of a food.