What are net carbs and how to calculate them
Net carbs are the carbohydrates that actually raise your blood sugar: total carbohydrate minus fiber, and minus part of any sugar alcohols. The idea is that fiber passes through mostly undigested, so it should not count toward the carbs your body absorbs. On a US label you do the subtraction yourself. On an EU label the "carbohydrate" figure already excludes fiber, so the number shown is already close to net carbs. The concept is useful for low-carb and keto diets, but it is an estimate, not an official measure.
Total carbs minus fiber minus ~half of sugar alcohols.
The carb figure already excludes fiber.
Practical estimate, not regulated.
The formula, and the EU vs US twist
On a US Nutrition Facts panel, carbohydrate includes fiber, so the calculation is: net carbs equal total carbohydrate minus fiber, minus roughly half of any sugar alcohols. On an EU label, fiber is listed separately and is not part of the carbohydrate line, so the "of which sugars" already sits inside a fiber-free carbohydrate total. That single regional difference causes endless confusion for people comparing products or apps across countries, and it is why the same food can look like it has different carbs depending on where the label was printed. Our explainer on how carbohydrate is grouped covers the underlying label logic.
Worked examples on real foods
| Food (per 100 g, illustrative) | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| Sweet potato | ~20 g | ~3 g | ~17 g |
| Multigrain bread | ~43 g | ~6 g | ~37 g |
| Pistachios | ~28 g | ~10 g | ~18 g |
| Pumpkin seeds | ~11 g | ~6 g | ~5 g |
Values on real products vary by brand, so always read the specific label. Notice how high-fiber foods like pistachios and pumpkin seeds shed a big chunk of their carbs once fiber is removed, which is exactly why they are popular on low-carb plans.
Where sugar alcohols complicate things
Keto and diabetic-friendly products often lean on sugar alcohols like erythritol, xylitol and maltitol, then subtract all of them to advertise very low net carbs. That is where the estimate gets slippery. Erythritol is largely absorbed and excreted with little blood-sugar effect, so subtracting it is fair. Maltitol, however, does raise blood sugar meaningfully, so subtracting it in full overstates how "low-carb" a product really is. A cautious approach is to subtract only about half of sugar alcohols, and to trust how a food affects you over any marketing claim.
Should you even count net carbs?
For most people eating a balanced diet, no. Net carbs only matter if you are deliberately limiting carbohydrate, such as on keto, or managing blood sugar with clinical guidance. If that is not you, tracking total carbohydrate and prioritising fiber is simpler and just as effective. If it is you, use net carbs as a practical guide rather than a precise truth, and compare two products directly with the comparison tool when the labels play games with fiber or sugar alcohols.
Bottom line
Net carbs are total carbs minus fiber, minus part of any sugar alcohols, meant to capture the carbs that actually reach your bloodstream. Remember the EU label already excludes fiber, treat sugar-alcohol subtractions with suspicion, and only bother with the number if you are genuinely limiting carbohydrate.
Sources
Common questions
What are net carbs?
Net carbs are the carbohydrates that actually raise blood sugar: total carbohydrate minus fiber, and minus part of any sugar alcohols. They are used mainly on low-carb and keto diets.
How do I calculate net carbs?
On a US label, subtract fiber and about half of sugar alcohols from total carbohydrate. On an EU label, the carbohydrate figure already excludes fiber, so net carbs are close to the carbohydrate value shown.
Are net carbs an official measure?
No. Net carbs are not a regulated term. They are a practical estimate, and aggressive labelling of sugar alcohols can understate the real blood-sugar impact of a product.