Net carbs are the carbohydrates your body actually digests and turns into glucose. If you have ever stared at a nutrition label and wondered why two foods with the same total carbs behave so differently, net carbs are the missing piece — and the math behind them is simpler than most articles make it look.
The quick answer: Net carbs = total carbs − fiber − sugar alcohols. Fiber and most sugar alcohols are not fully digested, so they barely raise blood sugar. That is the whole idea in one line. The rest of this guide shows you how to use it, with real numbers, a full food chart, and the honest caveats most articles skip.
The Formula, in Plain English
Every net carb calculation uses the same three numbers from the nutrition label:
Net carbs = Total carbohydrates − Dietary fiber − Sugar alcohols
Here is how to read them on a label. Find the “Total Carbohydrate” line first — that is your starting number. Directly underneath it, indented, you will see “Dietary Fiber.” That is the first subtraction. Some labels also list “Sugar Alcohols” under the sugars section; if a product has none, that line may be missing entirely, in which case you simply treat it as zero and subtract only the fiber.
A worked label example makes it concrete. Imagine a protein bar whose label reads: total carbohydrates 22 g, dietary fiber 9 g, sugar alcohols 6 g. The math is 22 − 9 − 6 = 7 g of net carbs. The bar still contains 22 g of carbohydrate in total, but only about 7 g of it is expected to raise your blood sugar in any meaningful way. That gap between the two numbers is exactly why low-carb eaters track net carbs instead of total carbs.
One detail worth knowing: fiber is already included in the total carbohydrate number, so you are not double-counting anything when you subtract it. You are simply removing the part your body does not digest. The same logic applies to sugar alcohols, with one important exception we will get to below — not all sugar alcohols behave the same way.
Worked Examples: Net Carbs in Real Foods
Watch how fiber changes the story. An avocado looks high-carb at first glance, but most of those carbs are fiber. A protein bar looks modest until you check whether sugar alcohols are doing the heavy lifting. All values below are typical values per serving, and the math is shown so you can check it yourself.
| Food | Total carbs | Fiber | Sugar alcohols | Net carbs |
|---|---|---|---|---|
| Avocado (1 whole) | 13 g | 10 g | 0 g | 3 g |
| Raspberries (1 cup) | 15 g | 8 g | 0 g | 7 g |
| Broccoli (1 cup) | 6 g | 2 g | 0 g | 4 g |
| Cauliflower (1 cup) | 5 g | 2 g | 0 g | 3 g |
| Strawberries (1 cup) | 12 g | 3 g | 0 g | 9 g |
| A typical protein bar | 22 g | 9 g | 6 g | 7 g |
Notice the pattern: whole foods earn their low net carb counts honestly, through fiber. The protein bar reaches a similar number only with help from sugar alcohols — which is fine, but it is a different kind of low, and the caveats section below explains why it matters.
Net Carb Chart: 15 Common Low-Carb Foods
Use this chart as a quick reference. Values are typical per serving; brands and ripeness shift them a little, but the order of magnitude is stable. For full meals built from these foods, see our Low-Carb Meals guide.
| Food (serving) | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| Eggs (2 large) | 1 g | 0 g | 1 g |
| Salmon (4 oz) | 0 g | 0 g | 0 g |
| Chicken breast (4 oz) | 0 g | 0 g | 0 g |
| Olive oil (1 tbsp) | 0 g | 0 g | 0 g |
| Spinach, raw (1 cup) | 1 g | 1 g | 0 g |
| Cheddar cheese (1 oz) | 0 g | 0 g | 0 g |
| Zucchini (1 cup) | 4 g | 1 g | 3 g |
| Cucumber (1 cup) | 4 g | 1 g | 3 g |
| Mushrooms (1 cup) | 3 g | 1 g | 2 g |
| Cauliflower (1 cup) | 5 g | 2 g | 3 g |
| Green beans (1 cup) | 7 g | 4 g | 3 g |
| Greek yogurt, plain (3/4 cup) | 5 g | 0 g | 5 g |
| Almonds (1 oz) | 6 g | 3 g | 3 g |
| Walnuts (1 oz) | 4 g | 2 g | 2 g |
| Pecans (1 oz) | 4 g | 3 g | 1 g |
The takeaway from the chart is simple: animal proteins, fats and above-ground vegetables are nearly free in net carb terms. Nuts and dairy cost a few grams each, which is why portions matter more than the food itself.
Net Carbs vs Total Carbs: the Honest Caveats
Net carbs are a useful tool, not a law of nature — and the honest articles say so. First, “net carbs” is not an FDA-defined label term. You will not find it printed on a US nutrition label as an official line; it is a calculation people do from the label, which means different brands can present it differently on the front of the pack.
Second, sugar alcohols are not all equal. Erythritol is barely metabolized at all, so counting it as zero is reasonable. Maltitol, on the other hand, is partly digested and raises blood sugar roughly half as much as regular sugar — so a bar sweetened with maltitol whose package claims “2 g net carbs” may behave more like 5 or 6 g in your body. If a product leans hard on a front-of-pack net carb claim, flip it over and check which sweetener is doing the work.
Third, the diabetes note matters. People with diabetes are commonly advised to count total carbs rather than net carbs when dosing insulin or managing blood sugar, because total carbs are the more conservative, predictable number. If that is you, follow your doctor’s guidance rather than a blog post — including this one. Net carbs are a planning tool for low-carb eating, not medical advice.
How Many Net Carbs per Day?
It depends on the plan, but the usual ranges are consistent. A keto diet typically runs 20–50 g of net carbs per day — the strict end where ketosis becomes the goal. A general low-carb approach usually lands around 50–100 g of net carbs per day, which leaves room for more vegetables, berries and dairy. Note that both figures are net figures; in total carb terms, the same days would read higher because of all the fiber in the vegetables.
If you want the strict version fully planned, our Keto Meal Plan lays out a 7-day menu at keto levels. If you would rather vary your carbs across the week — more on training days, fewer on rest days — our carb cycling guide shows how that works. And remember that net carbs are only half the picture: calories still decide whether you gain or lose weight, so find your own number with our Maintenance Calories Calculator before you set any carb target.
Common Mistakes When Counting Net Carbs
Trusting front-of-pack claims with maltitol. As above, a “3 g net carbs” bar sweetened with maltitol can act like considerably more. Read the ingredients, not just the badge.
Subtracting fiber twice. Fiber is already inside the total carbohydrate number. Subtract it once. If you also subtract it from something else — or count a high-fiber food’s net carbs and then subtract the fiber again from your daily total — your day’s math quietly drifts low.
Forgetting drinks and sauces. A sugar-free soda is genuinely near zero, but a “low-carb” barbecue sauce, a sweetened coffee drink or a couple of tablespoons of ketchup can each add 3–8 g of net carbs that never made it into your meal plan. Sauces are the classic leak in an otherwise tidy day of counting.
The bottom line is refreshingly simple: total carbs minus fiber minus sugar alcohols, checked against the label rather than the marketing. Do that honestly, keep an eye on which sweetener is in the product, and net carbs will serve you well — whether your target is 30 g a day on keto or 80 g a day on a general low-carb plan.
What are net carbs?
Net carbs are the carbohydrates your body actually digests: total carbs minus fiber minus sugar alcohols. Fiber and most sugar alcohols pass through without being fully digested, so they barely raise blood sugar.
How do you calculate net carbs?
Use the formula: net carbs = total carbs − fiber − sugar alcohols. For example, a whole avocado has 13 g of total carbs and 10 g of fiber, so 13 − 10 = 3 g of net carbs.
Are net carbs accurate?
They are a useful estimate, not an exact measurement. Net carbs is not an FDA-defined label term, and sugar alcohols differ: erythritol counts as roughly zero, while maltitol counts about half. Package claims can mislead when maltitol does the sweetening.
How many net carbs can I eat on keto?
A keto diet typically runs 20–50 g of net carbs per day. A general low-carb approach usually lands around 50–100 g of net carbs per day. Both figures are net figures, so the same days read higher in total carbs.
Should diabetics count net carbs or total carbs?
People with diabetes are commonly advised to count total carbs rather than net carbs, because total carbs are the more conservative and predictable number. Follow your doctor’s guidance on which number to use.
