Free net carbs calculator
Find the net carbs in any food in two seconds. Enter the total carbohydrate, fiber, and sugar alcohols from the label and the calculator returns net carbs (total − fiber − sugar alcohols), what it subtracted, and handles the US vs EU labeling difference — updated live, as you type.
On this page15 sections
| Total carbohydrate | 24 g |
| − Dietary fiber | 9 g |
| − Sugar alcohols | 8 g |
| = Net carbs | 7 g |
US method. On an EU, UK, or Australian label the carbohydrate figure already excludes fiber — enter it as the total and set fiber to 0.
Net carbs is an estimate and not an FDA-defined term; individual absorption varies. Are net carbs scientifically valid?
Results are estimates. Consult a professional.
What are net carbs?
Net carbs are the carbohydrates your body actually digests and absorbs — the ones that get broken down into glucose and raise your blood sugar. They are sometimes called digestible carbs or impact carbs. You get them by taking the total carbohydrate in a food and subtracting the parts that pass through largely unabsorbed: dietary fiber and most sugar alcohols. That is exactly what this net carbs calculator does the moment you type in a label's numbers.
Net carbs vs total carbs — why they differ
Total carbs is every gram of carbohydrate in a food: starches, sugars, and fiber together. Net carbs strips out the carbohydrate your body can't use for energy. A cup of raspberries has about 15 g of total carbs but only around 7 g of net carbs, because roughly 8 g is fiber. For someone counting carbs on keto, that gap is the whole point — it is the difference between a food that fits the day and one that blows the budget.
How to calculate net carbs
Calculating net carbs from a US nutrition label is a short, repeatable process. Read the three numbers off the Nutrition Facts panel, then do one subtraction.
- Start with total carbohydrate. This is the top carb line on a US label, and it already includes fiber and sugar alcohols within it.
- Subtract the dietary fiber. Fiber is listed indented under total carbohydrate; your body doesn't absorb most of it for energy.
- Subtract sugar alcohols. If the food lists sugar alcohols (polyols), remove them too — in full as a simple default, or half for types like maltitol (see below).
Why keto and low-carb dieters track net carbs
The ketogenic diet works by keeping carbohydrate low enough that the body shifts from burning glucose to burning fat for fuel — a state called ketosis. Most keto plans cap intake at roughly 20–50 g of net carbs a day. Because fiber and most sugar alcohols don't spike blood sugar or knock you out of ketosis, counting net carbs instead of total carbs lets you eat more fibrous vegetables, nuts, and berries while staying under that ceiling.
Atkins popularized the net-carb concept in the early 2000s, and low-carb and keto communities have used it ever since. It is the working number for anyone managing carbohydrate load — keto, Atkins, or general low-carb eating. To build the rest of your day around it, pair this tool with the macro calculator and the carbohydrate calculator.
Fiber and sugar alcohols explained
Why fiber is subtracted
Dietary fiber is carbohydrate your small intestine cannot digest. Insoluble fiber passes through essentially intact; soluble fiber is fermented by gut bacteria but contributes little to blood glucose. Because it isn't absorbed as usable carbohydrate, the net-carb method subtracts it in full. This is why high-fiber foods like leafy greens, avocado, chia seeds, and raspberries are keto staples — their total carbs look high, but their net carbs are low.
Why sugar alcohols are subtracted (and when only halfway)
Sugar alcohols, or polyols, are sweeteners like erythritol, xylitol, maltitol, and sorbitol used in low-carb and sugar-free products. The body absorbs them only partially, so they raise blood sugar less than regular sugar — but by different amounts. A common, more conservative rule is to subtract only half the grams of most sugar alcohols, and to subtract erythritol and allulose in full because their glycemic impact is essentially zero.
| Sugar alcohol | Typical handling | Note |
|---|---|---|
| Erythritol | Subtract in full | Near-zero glycemic impact; mostly excreted unchanged |
| Allulose | Subtract in full | Rare sugar; minimal blood-sugar effect |
| Xylitol | Subtract half | Partially absorbed; moderate glycemic response |
| Sorbitol | Subtract half | Partially absorbed; can cause GI upset in volume |
| Maltitol | Subtract half (or less) | Most absorbed; raises blood sugar nearly like sugar in some people |
The calculator subtracts sugar alcohols in full by default. For maltitol-heavy products, enter half the grams (or use the half rule) for a conservative estimate.
A worked example using the net carbs calculator
Sam is on keto and wants to know whether a protein bar fits his 25 g daily net-carb budget. The wrapper lists 24 g total carbohydrate, 9 g dietary fiber, and 8 g sugar alcohols per bar. Here is how the calculator gets to net carbs.
Step 1 — Start with total carbohydrate
The label's top carb line reads 24 g. On a US label this already includes the fiber and sugar alcohols, so it is the starting point — not the end of the story.
Step 2 — Subtract fiber and sugar alcohols
| Line | Grams |
|---|---|
| Total carbohydrate | 24 g |
| − Dietary fiber | 9 g |
| − Sugar alcohols | 8 g |
| = Net carbs | 7 g |
Step 2 result: 24 − 9 − 8 = 7 g net carbs (full subtraction).
Step 3 — Read the result and decide
One caution worth checking. If those 8 g of sugar alcohol were mostly maltitol, the conservative half rule would subtract only 4 g, giving 24 − 9 − 4 = 11 g net carbs — still under budget, but higher. When a product leans on maltitol, enter half the sugar-alcohol grams for a safer estimate. The next section explains why the label's country changes the math too.
Net carbs on US vs EU food labels
Here is the single most common mistake people make, and the gap most net-carb guides skip: the math depends on where the label was printed. The United States and Canada count carbohydrate one way; the EU, UK, and Australia count it another. Subtract fiber on the wrong label and you double-count it.
| Region | What "carbohydrate" on the label means | How to get net carbs |
|---|---|---|
| US & Canada | Total carbohydrate — includes fiber and sugar alcohols | total carbs − fiber − sugar alcohols |
| EU, UK & Australia | Available carbohydrate — fiber already excluded, listed separately as "fibre" | carbohydrate − polyols (do NOT subtract fiber again) |
Sources: US FDA 21 CFR 101.9; EU Regulation (EU) No 1169/2011.
In other words, the "carbohydrate" number on a European or Australian label is already close to what an American would call net carbs — fiber has been removed for you. So on an EU/UK label, enter the carbohydrate figure as your total, leave fiber at 0 in the calculator, and only subtract any sugar alcohols (polyols). On a US label, enter all three numbers as printed.
Net carbs in common keto foods
Seeing the total-versus-net gap across real foods makes the method click. These are approximate US values per common serving; always check the label, since brands and ripeness vary.
| Food (serving) | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| Avocado (1 medium) | 12 g | 10 g | 2 g |
| Raspberries (1 cup) | 15 g | 8 g | 7 g |
| Almonds (1 oz / 28 g) | 6 g | 3 g | 3 g |
| Broccoli (1 cup, raw) | 6 g | 2 g | 4 g |
| Chia seeds (1 oz / 28 g) | 12 g | 10 g | 2 g |
| Plain Greek yogurt (170 g) | 6 g | 0 g | 6 g |
Approximate values; fiber drives the gap. Whole, fibrous foods have far lower net carbs than their total carbs suggest.
Notice the pattern: the bigger the fiber line, the bigger the discount. That is why keto leans on avocado, nuts, seeds, and non-starchy vegetables — they deliver volume and nutrients for very few net carbs.
Are net carbs scientifically valid?
Net carbs is a useful estimate, not an exact science — and it helps to know its limits. The FDA does not recognize "net carbs"; there is no regulatory definition, which is why you won't see the term on a Nutrition Facts panel. The American Diabetes Association also doesn't endorse it as a clinical measure. The concept rests on a reasonable premise — that fiber and most sugar alcohols are poorly absorbed — but that premise isn't perfectly true for everyone.
- Not all fiber behaves the same. Some isolated and fermentable fibers are partially metabolized and can contribute a little glucose or energy, so subtracting 100% slightly overstates the discount.
- Sugar alcohols vary by person and type. Maltitol can raise blood sugar nearly as much as sugar in some people, while erythritol barely registers — a flat subtraction hides that spread.
- Individual response differs. Gut bacteria, the rest of the meal, and your own metabolism all shift how much of a "net carb" you truly absorb.
The practical takeaway: net carbs is a sound planning tool for keto and low-carb eating, and most dietitians in the low-carb space use it. But if you manage diabetes or are tracking tightly, treat the number as a guide, watch your own glucose response, and lean toward the conservative half rule for sugar alcohols.
How to count net carbs accurately
A few habits keep your net-carb counting honest and consistent:
- Check the label's country first. US/Canada labels include fiber in total carbs; EU/UK/Australia labels don't. Subtract fiber only when it's actually inside the carb number.
- Count per serving, then multiply. Net carbs are listed per serving — if you eat two servings, double the net carbs.
- Be conservative with maltitol. For products sweetened with maltitol, subtract only half the sugar alcohols, or none, if your blood sugar reacts.
- Prefer whole foods. Whole-food net carbs (vegetables, nuts, berries) are more predictable than the engineered net carbs of "keto" processed snacks.
Data sources and methodology
This calculator uses the standard US net-carb convention — net carbs = total carbohydrate − dietary fiber − sugar alcohols — and floors the result at zero. The labeling rules behind it come from the US FDA (total carbohydrate is calculated "by difference" and includes fiber, per 21 CFR 101.9) and the EU (carbohydrate is defined as available carbohydrate, fiber excluded, under Regulation (EU) No 1169/2011). The fiber and sugar-alcohol handling follows the consumer net-carb conventions used by Atkins, Healthline, and Diet Doctor. "Net carbs" itself is a dietary convention, not an FDA-recognized nutrient.
US FDA — Nutrition labeling, 21 CFR 101.9 (carbohydrate by difference).EU Regulation (EU) No 1169/2011 — food information to consumers (carbohydrate definition).Frequently asked questions about the free net carbs calculator
About this net carbs calculator
This net carbs calculator runs entirely in your browser. The label numbers you type stay on your device — nothing is sent to a server, logged, or shared. It uses the US net-carb convention (total carbohydrate minus fiber and sugar alcohols), floors the result at zero, and supports full or half subtraction of sugar alcohols, updating instantly.
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