Net carbs calculator
Total carbs minus fiber minus sugar alcohols. The keto formula used by North American nutritionists to estimate the actual glycemic impact of a food.
Net carbs
—
g
On the nutrition label, the "Total Carbohydrate" line
"Dietary Fiber" line
Erythritol, xylitol, maltitol, allulose. Often labeled "Sugar alcohols"
Per
Common keto foods
Quick fill:
Tracking net carbs?
Cetona generates a 7-day keto plan adapted to your country, calculates your macros and builds your shopping list automatically.
Try 3 days freeThe formula
Net carbs = Total carbs − Fiber − Sugar alcohols Fiber is not digested and does not raise blood sugar. Sugar alcohols (erythritol, xylitol, etc.) have very low glycemic impact. Subtracting both gives an estimate of the carbs that actually affect your body. This formula is standard in North America. In the UK, labels already show "carbohydrates excluding fibre" by default.
Why count net carbs on keto
The ketogenic diet relies on very low carb intake to stay in ketosis. Counting total carbs only is more restrictive than necessary: fiber and most sugar alcohols don't kick you out of ketosis. Counting nets lets you include more leafy greens, nuts and keto-sweetened products without fearing you'll exit ketosis. Stricter approaches (e.g. carnivore or therapeutic keto) count totals — choose what works for you.
How to read a nutrition label
- 1Find "Total Carbohydrate" — the top number.
- 2Find "Dietary Fiber" and subtract it.
- 3Find "Sugar Alcohols" (sometimes hidden under "Total Sugars"). Subtract that too.
- 4Double-check the serving size — "per 100g" vs "per serving" changes everything.
- 5The result = your net carbs for that serving. Multiply if you eat multiple servings.
FAQ
Do sugar alcohols kick you out of ketosis?▾
Erythritol has a glycemic index of 0 (zero impact). Xylitol and maltitol have partial impact — count them at 50%. Allulose and stevia are neutral. Read the label: if the sugar alcohol isn't specified, subtract it fully as a first approximation.
How many net carbs per day on keto?▾
The standard target is 20-30g per day to stay in ketosis. Some people tolerate up to 50g (moderate keto or "lazy keto"). It's very individual — a ketone test (urine or blood) confirms your level.
Net carbs or total carbs?▾
Net carbs for most people. Total carbs if you're stalled, doing therapeutic keto (epilepsy, etc.) or if you react strongly to sugar alcohols.
My label doesn't show fiber separately.▾
European labels: "Carbohydrates" already excludes fiber in some countries (UK, Ireland) and includes it in others. Check the country of origin.
Does Cetona count nets or totals?▾
Cetona shows net carbs by default in your plans (target 20-30g/day). You can switch to total carbs in settings.
Other languages