Net Carbs (Net Carbs)
Net carbs are total carbohydrates minus fiber (and sometimes sugar alcohols) — the carbohydrate value relevant for keto, low-carb, and diabetic management.
Net carbs are total carbohydrates minus dietary fiber (and, in some calculation methods, minus sugar alcohols). The rationale: fiber is largely indigestible by humans, so it doesn’t contribute meaningful glycemic load or metabolizable energy. Sugar alcohols (erythritol, xylitol, maltitol) are partially digestible with varying glycemic impact.
The standard formula:
net_carbs = total_carbs − fiber − (sugar_alcohols × adjustment_factor)
The adjustment factor for sugar alcohols varies by alcohol (erythritol: 1.0, full subtraction; maltitol: ~0.5, partial subtraction). Different keto resources and tracking apps use different conventions — for keto compliance, follow the convention of the framework you’re following.
Why net carbs matter
For keto and low-carb diets, net carbs (not total carbs) determine whether you stay in ketosis. The standard keto threshold is <20-50g net carbs per day. Total carbs above that threshold may still be keto-compatible if the difference is fiber.
For diabetic management, net carbs approximately predict postprandial blood glucose response. Fiber’s near-zero glycemic load makes total-carb counts misleading for users managing blood sugar — a 30g-total-carb meal with 20g fiber will produce a much smaller glucose response than a 30g-total-carb meal with 0g fiber.
For general weight loss (non-keto), total carbs and net carbs both work. The distinction matters mainly when carb intake is being deliberately restricted.
Which apps display net carbs
- Carb Manager — net carbs are the first-class metric, displayed prominently
- Cronometer — net carbs calculable; displayed alongside total carbs
- MyFitnessPal Premium — net carb display available
- MacroFactor — net carbs accessible
- Lose It!, Yazio, Lifesum — total carbs displayed by default; net carbs less prominent
For users specifically following keto, low-carb, or managing diabetes, Carb Manager is the purpose-built choice and the net-carb-first display materially reduces friction compared to general trackers where net carbs are a secondary metric.