What Are Net Carbs? Total Carbohydrate Minus Fiber

Carbohydrate on a food label is a single total, and that total includes fiber. Net carbs is a way of reading it. You take the total carbohydrate, subtract the fiber, and call what is left the net. People who count carbohydrates, for instance on a low-carbohydrate diet, often track this figure instead of the total.

The first thing to understand is that "net carbs" is not something a laboratory measures. USDA reports total carbohydrate and, separately, dietary fiber. The net is arithmetic done afterwards, and different apps and brands do it differently. This page describes what CalorTracker does, so you can compare it with what you see elsewhere.

How we calculate it

The rule is one subtraction: net carbs per 100 grams = total carbohydrate minus fiber, taken from USDA FoodData Central and rounded to one decimal place. Two details keep it honest:

• It never goes below zero, so a food whose reported fiber exceeds its reported carbohydrate shows no net carbs rather than a negative number.
• It needs both values. If USDA reports no fiber for a food, we show no net carbs at all, because treating a missing value as zero would give a wrong answer that looks right. A nutrient USDA did not report is kept as missing everywhere on the site.

We do not subtract sugar alcohols or any other component. The method sits with the rest of the food calculations on how we calculate.

Worked example

Two foods with very different fiber show how much the subtraction matters. Values are per 100 grams, from their food pages:

Almonds start at 21.55 g of total carbohydrate and end at 9.1 g once their 12.5 g of fiber is taken out. Broccoli goes from 6.64 g to 4 g. In both cases the net figure is the one the food pages and the low-carbohydrate lists use when they rank foods.

Where it shows up

Our low-carb vegetables list ranks foods by this figure, and the food pages show it in the diet-fit section next to protein per 100 calories. Because it is derived from the same data as everything else on the site, a change in a food's USDA record changes its net carbs with no one editing the page.

What net carbs do not tell you

Net carbs are a convention, and conventions differ. A packaged product may print its own net figure, calculated by the maker's rules, and it can disagree with ours for the same food. Subtracting fiber also says nothing about how a particular food affects a particular person.

The figure counts carbohydrate only. It does not show calories, and calories still come from all three macronutrients. If you are managing a medical condition such as diabetes, take carbohydrate targets from your care team rather than from a general glossary entry.