What are net carbs?
Carbohydrate is not one single thing. On a nutrition label it covers starches, sugars, fiber and, in some foods, sugar alcohols. Starches and sugars are digested and absorbed, so they count toward the energy you get from a meal. Fiber mostly passes through your gut undigested, and sugar alcohols are only partly absorbed. Net carbs is the name for what is left when you take those last two out.
The basic formula is simple:
Net carbs = total carbs − fiber − sugar alcohols
The idea is popular on keto and other low-carb diets, where people want a daily number that reflects the carbs that actually count toward their limit. It also rewards high-fiber foods. Avocado, raspberries and chia seeds look fairly carb-heavy on paper, but most of their carbs are fiber, so their net carbs are low.
One thing to know up front: net carbs is not a regulated label term in the US or the EU. No authority defines exactly what may be subtracted, so a "net carbs" figure printed on the front of a package is the brand's own calculation. The nutrition facts panel is the regulated part of the label, and it gives you everything you need to do the math yourself.
Total vs net carbs
Total carbs is everything: starches, sugars, fiber and sugar alcohols added together. Net carbs is the part that is left once fiber and sugar alcohols are subtracted. For foods with little fiber, the two numbers are almost the same. For high-fiber foods, the gap can be large.
A few examples, with values from USDA FoodData Central (see our carbs in food chart for more foods):
- White bread, 1 slice: 12 g total carbs, 0.5 g fiber, so 11.5 g net carbs. Almost no difference.
- Apple, 1 medium: 25 g total carbs, 4.5 g fiber, so 20.5 g net carbs.
- Lentils, cooked, 1/2 cup: 20 g total carbs, 8 g fiber, so 12 g net carbs.
- Raspberries, 1 cup: 15 g total carbs, 8 g fiber, so 7 g net carbs.
- Avocado, half: 9 g total carbs, 6.5 g fiber, so 2.5 g net carbs.
- Chia seeds, 1 oz: 12 g total carbs, 10 g fiber, so 2 g net carbs.
Where you live changes what the label shows, and this is the most common source of confusion. US labels list total carbohydrate, which includes fiber, with fiber shown on its own line underneath. EU and UK labels work differently: their carbohydrate line already excludes fiber, which is listed separately. So the carbohydrate figure on a European label is already much closer to net carbs. If you subtract fiber from it again, you subtract it twice and end up too low.
Sugar alcohols deserve a note of their own. They are sweeteners like erythritol, xylitol, sorbitol and maltitol, common in low-sugar sweets, protein bars and chewing gum. Some brands subtract all of them when they print net carbs. That is a simplification: erythritol passes through the body largely unused, but others, maltitol in particular, are partly absorbed and do add some usable carbs. Treat subtracting sugar alcohols as an approximation. Some people subtract only half of the maltitol, or skip the sugar alcohol step altogether for a more cautious count.
Net carb calculator
Enter the numbers from the label in grams. The calculator subtracts fiber and sugar alcohols from total carbs and never goes below zero. Leave a field empty if the label does not list it.
Net carbs: 0 g
On a US label, enter the total carbohydrate as it is. On an EU or UK label, the carbohydrate line already excludes fiber, so enter that figure as total carbs and leave the fiber field empty. Otherwise the fiber gets subtracted twice.
Worked example with a real label
Take a typical low-sugar snack bar. The numbers below are a made up example with round figures, not a specific product, but they are laid out the way you would find them on the package. The same bar is shown twice: once with a US nutrition facts panel and once with an EU style nutrition declaration.
| Per bar | US label | EU label |
|---|---|---|
| Total carbohydrate | 24 g | not listed |
| Dietary fiber (fibre) | 9 g | 9 g |
| Sugar alcohols (polyols) | 8 g | 8 g |
| Carbohydrate (excluding fiber) | not listed | 15 g |
| Net carbs | 24 − 9 − 8 = 7 g | 15 − 8 = 7 g |
On the US label, total carbohydrate is 24 grams. Underneath it you find dietary fiber, 9 grams, and sugar alcohol, 8 grams. Both are already part of the 24. Subtract them and you get 24 − 9 − 8 = 7 grams of net carbs. If you only subtract the fiber, you get 15 grams.
On the EU label, the carbohydrate line says 15 grams. Fiber is listed on a separate line and is not part of that 15. The polyols (the EU word for sugar alcohols), 8 grams, when listed, are shown as a sub line and are included in the carbohydrate figure. So you only subtract the polyols: 15 − 8 = 7 grams of net carbs. Same bar, same answer, but a different route to get there.
If this bar were sweetened mostly with maltitol, the real number would sit somewhere between 7 and 15 grams, because part of the maltitol is absorbed. That is why the sugar alcohol step is best treated as an estimate rather than an exact figure.
Why some people count total carbs instead
Net carbs are not the only way to go, and plenty of people deliberately stick with total carbs. The main reasons are practical.
Consistency. The most important rule in carb counting is to use the same method every time. Mixing net and total carbs from day to day makes your numbers impossible to compare. If you already track total carbs and it works for you, there is no need to switch. Our guide on how to count carbs covers the basics either way.
Simplicity. Total carbs on a US label need no math at all. There is no question about which sugar alcohols to subtract, or how much, and no risk of trusting a front of pack net carb figure that was calculated generously.
Labels differ by country. If you travel, shop at international stores or follow recipes from abroad, you will see both label styles. Knowing that a European carbohydrate figure already excludes fiber helps, but it is easy to slip up. Some people prefer one approach they can apply the same way everywhere.
Whichever you choose, pick one and stay with it. If you manage a medical condition, your care team sets your carb targets and can tell you which number to track.
Source for the food values: USDA FoodData Central (fdc.nal.usda.gov), per typical portion, carbs rounded to whole grams and fiber to the nearest 0.5 g. The snack bar label is an illustrative example, not a real product.