Calculate net carbohydrates by subtracting dietary fibre and sugar alcohols from total carbs, with keto-threshold context.
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Health & Nutrition
Net carbohydrates are the carbs that significantly impact blood glucose: total carbohydrates minus dietary fibre and the absorbable fraction of sugar alcohols. They are used primarily in ketogenic and low-carb diet planning.
Dietary fibre passes through the digestive system largely undigested and has minimal impact on blood glucose. Regulatory bodies in both the US and EU classify fibre separately from available carbohydrates on nutrition labels, reflecting its different metabolic fate.
Most sugar alcohols (maltitol, xylitol, sorbitol) are partially absorbed and have a glycaemic impact roughly half that of regular sugar, so a 50% deduction is the conservative standard. Erythritol is the exception: it is absorbed in the small intestine but excreted mostly unchanged in urine, with negligible blood glucose effect, so it is treated as fully deductible.
Frequently asked questions
Not in most jurisdictions. "Net carbs" is a marketing term, not a regulated label category. US nutrition facts panels list total carbohydrates with fibre and sugar alcohols as sub-items. EU labels show "of which polyols" separately.
Most ketogenic diet protocols aim for 20–50 g net carbs per day, with strict keto often targeting ≤ 20 g. This calculator flags ≤ 20 g as a common keto-threshold indicator, though individual carbohydrate tolerance varies.
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