Net Carbs Calculator — Keto & Low-Carb Diets
Net carbs are the carbohydrates that significantly raise blood sugar: total carbs minus dietary fiber (not digested) and some or all sugar alcohols. Enter your nutrition-label numbers to find net carbs in seconds — and choose the deduction method that matches your dietary approach.
g
g
g
Deduction method
Total carbs minus fiber and deducted sugar alcohols
- 1
Fiber deducted
8Dietary fiber is not digested and is fully subtracted from total carbs. - 2
Sugar-alcohol deduction
4 (full deduction) = 4 - 3
Net carbs
25 − 8 − 4 = 13
How does this calculator work?
Net carbs = Total carbs − Fiber − Sugar alcohols (full deduction) or − 0.5 × Sugar alcohols (half deduction). Fiber is fully deducted because it is not digestible. Sugar-alcohol deduction depends on the specific polyol — erythritol is often fully deducted; maltitol only partially. Use the method that matches your dietary protocol.
Formula
How this is calculated
Dietary fiber passes through the small intestine largely undigested, so it contributes little to blood glucose. Regulatory bodies (including the FDA in the US) subtract fiber from total carbohydrates to report "available carbohydrates" — the basis of the net-carbs concept.
Sugar alcohols (polyols) have a more complex picture. Some, like erythritol, have a very low glycemic index and are often fully deducted. Others, like maltitol, are absorbed at roughly 50 % efficiency and can raise blood sugar noticeably — making a full deduction misleading. The "full deduction" method, used by Atkins and most US keto apps, subtracts all sugar alcohols. The "half deduction" method, preferred by many European and evidence-based practitioners, subtracts only half to account for partial absorption.
Note that individual responses vary: gut microbiome composition, metabolic health, and the specific polyol all affect how much blood sugar rises after eating a food. If you are managing diabetes or following a medically supervised diet, consult a registered dietitian about which method is appropriate. The nutrition label value for fiber already excludes insoluble residues in jurisdictions using Atwater factors; double-check which fibre figure your label reports.
Frequently asked questions
It depends on the polyol. Erythritol is almost entirely excreted unabsorbed and is usually fully deducted. Xylitol and sorbitol have moderate glycemic impact; halving is more accurate. Maltitol is absorbed at roughly 50 % efficiency. If your food uses a blend, the "half deduction" method is a conservative and broadly applicable default.
Not always. US nutrition labels use AOAC fibre (a broader analytical definition) and explicitly include "dietary fibre" as a subcomponent of total carbohydrates. European labels report total carbohydrates after subtracting fibre at the analytical stage, so the "carbohydrate" figure already excludes fibre and no further deduction is needed. Always check which convention your label follows.
No. Net carbs count the grams of carbohydrate that are absorbed; glycemic load (GL) weights those grams by the food's glycemic index (GI), giving a measure of the actual blood-glucose response. A food can have low net carbs but a high GI (e.g. pure glucose), or moderate net carbs with a low GI (e.g. legumes). Net carbs is a simpler proxy; GL is more predictive of glucose impact.
Also known as
TG we-Calculate Editorial Team. (2026). Net Carbs Calculator — Keto & Low-Carb Diets [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/net-carbs-calculator
TG we-Calculate Editorial Team. "Net Carbs Calculator — Keto & Low-Carb Diets." TG we-Calculate. 2026. https://we-calculate.com/calculator/net-carbs-calculator.
TG we-Calculate Editorial Team, "Net Carbs Calculator — Keto & Low-Carb Diets," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/net-carbs-calculator
@misc{wecalculate_net_carbs_calculator, title = {Net Carbs Calculator — Keto & Low-Carb Diets}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/net-carbs-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?