Net Carbs and Macros Explained

If you follow a keto diet, you will hear two phrases all the time: net carbs and macros. They sound technical, but the math is simple. This guide explains what they mean, how to calculate them, how to read a U.S. nutrition label, and how to set daily targets that make sense for you.

This is general education, not medical advice. Individual needs differ, so talk to a doctor or registered dietitian before making big changes to how you eat.

What net carbs are

Carbohydrates include sugar, starch, and fiber. Your body digests sugar and starch into glucose, which raises blood sugar. Fiber is different: it is a carbohydrate your body cannot fully digest, so it has a much smaller effect on blood sugar.

Net carbs are the carbohydrates that are likely to affect your blood sugar. Most keto plans count net carbs instead of total carbs, because a large portion of the carbs in many vegetables is fiber.

Net carbs = total carbs − fiber − sugar alcohols

The formula has a few caveats, which we explain below.

How to calculate net carbs

Look at the Nutrition Facts panel and find three lines:

1. Total Carbohydrate
2. Dietary Fiber
3. Sugar Alcohols (not every label lists this)

Example 1: a whole food

A medium avocado, roughly 150 grams, contains approximately:

• Total carbs: 12.8 g
• Fiber: 10.1 g
• Net carbs: 12.8 − 10.1 = 2.7 g

Values are approximate. Check the label or a database such as USDA FoodData Central for exact amounts.

Example 2: a packaged snack

A keto bar lists:

• Total carbs: 14 g
• Fiber: 6 g
• Erythritol: 5 g
• Net carbs: 14 − 6 − 5 = 3 g

Example 3: when the label does not list sugar alcohols

If the label has no sugar alcohol line but the ingredients include maltitol, sorbitol, or xylitol, the carbs from those ingredients are in the total. Be careful: they may affect you more than erythritol. When in doubt, count them.

Why "net carbs" is not a regulated term

In the United States, the term "net carbs" is not defined by the FDA. Each brand uses its own method, and some subtract ingredients that still affect blood sugar. The safest habit is to read the three numbers yourself and do the subtraction.

Fiber and sugar alcohols

Fiber

Subtracting fiber is standard on keto. It matters most with vegetables, nuts, seeds, and berries, which can be high in total carbs but low in net carbs. Vegetables such as spinach, cucumber, zucchini, and cauliflower stay low even before you subtract fiber.

Sugar alcohols

Sugar alcohols are sweeteners such as erythritol, xylitol, sorbitol, and maltitol. They are partly absorbed, so the effect on blood sugar differs:

Sweetener	Typical treatment
Erythritol	Usually subtracted in full
Allulose	Usually subtracted in full (listed under added sugars on some labels)
Xylitol	Often partly subtracted. Toxic to dogs
Sorbitol	Often partly subtracted
Maltitol	Can raise blood sugar significantly. Often limited or avoided

All sugar alcohols can cause gas or loose stools in large amounts. Start small. For baking and sweeteners, see Keto Sweeteners and Baking.

On this site, our recipes subtract fiber and sugar alcohols from total carbohydrate. Recipes that use erythritol, such as the Almond Flour Chocolate Chip Cookies and Lemon Cheesecake Bites, show the net carbs after that subtraction. See How We Calculate for our full method.

Protein, fat, and carbs: how macros fit together

"Macros" is short for macronutrients: carbohydrates, protein, and fat. Each provides energy:

Macro	Calories per gram
Carbohydrate	4
Protein	4
Fat	9

A simple order for setting macros

1. Carbs first. Choose a daily net carb target. See the next section.
2. Protein second. A common range is about 1.2 to 2.0 grams per kilogram of body weight, with 1.6 as a typical middle. People who are older, very active, or trying to preserve muscle often aim higher in the range.
3. Fat last. After carbs and protein, fat fills the remaining calories. Eat more if you are hungry and want to maintain or gain weight, and less if you are aiming for gradual weight loss.

A worked example

Suppose a person weighs 80 kg (176 lb) and needs about 2,000 calories per day, aiming for 30 g net carbs and 1.6 g protein per kg.

• Carbs: 30 g × 4 = 120 calories
• Protein: 80 × 1.6 = 128 g × 4 = 512 calories
• Fat: (2,000 − 120 − 512) ÷ 9 ≈ 152 g

That is roughly 6% carbs, 26% protein, and 68% fat. Your own numbers will differ. This is only an illustration, not a prescription.

Do I need to track everything?

Not necessarily. Some people track for a few weeks to learn portion sizes, then eat by habit. Others prefer to track long-term. Pick the method you will actually stick to.

Choosing your carb level

We use three levels. All are net carbs per day.

Level	Net carbs	Notes
Gentle Low-Carb	50 to 100 g	Flexible. Ketosis is not the goal.
Moderate Keto	20 to 50 g	The most common starting point.
Strict Keto	Under 20 g	Very low. Discuss with a doctor first.

Things that may influence your choice:

• Your goal. Some people want ketosis, others simply want to eat fewer refined carbs.
• Activity. Very active people sometimes tolerate more carbs.
• How you feel. If you feel unwell on a strict level, a higher level may be more comfortable and sustainable.
• Medical situation. Some conditions and medications make very low-carb eating inappropriate. See our beginner guide.

Reading nutrition labels

The U.S. Nutrition Facts label has what you need. Follow these steps:

1. Check the serving size first. The numbers apply to one serving, which may be much smaller than what you eat.
2. Find Total Carbohydrate. Note the grams.
3. Subtract Dietary Fiber.
4. Subtract sugar alcohols, if listed and if they are the type you subtract.
5. Check Added Sugars. If it is more than 0 g, think about whether the food fits.
6. Scan the ingredients for hidden starches and sugars, such as maltodextrin, dextrose, corn syrup, and honey.

Where carbs hide

Sauces and marinades, salad dressings, deli meats with added sugar, processed "keto" snacks, flavored coffee drinks, and canned soups can all contain more carbs than you expect.

A note on rounding

Labels round to the nearest gram, so small amounts add up. A "0 g" seasoning used generously can still contribute a gram or two.

How our calculator works

Our keto macro calculator gives you a starting point using the following steps. You can read the full details on How We Calculate.

1. Body measurements. We use your height and weight to estimate body mass index (BMI).
2. Resting energy. We estimate your resting calorie needs with the Mifflin-St Jeor equation, a widely used formula.
3. Activity. We multiply by an activity factor to estimate your daily energy use.
4. Goal and pace. If you choose weight loss, we apply a moderate calorie reduction and never go below a safety floor.
5. Macros. We set net carbs from your chosen level, protein from your body weight, and fat from the remaining calories.

These are estimates. Individual needs vary, and calculators cannot replace advice from a health professional. If you have a medical condition, take medication, or are pregnant or breastfeeding, talk to a doctor before using any calculator-based plan.

Putting it into practice

A few easy ways to keep net carbs under control:

• Build meals around protein and non-starchy vegetables. Try the Greek Salad Bowl with Grilled Chicken or the Loaded Cobb Salad.
• Choose recipes that show net carbs. Every recipe page lists net carbs per serving.
• Watch the "extras." Sauces, dressings, and drinks can add up.
• Keep a few go-to meals. Familiar recipes make tracking easy.

Where to go next

• Keto Diet for Beginners: the full starter guide.
• Keto Food List: what to eat and what to avoid.
• Keto macro calculator: get your daily targets.
• Keto recipes under 5 g net carbs: easy ways to stay on target.
• Mediterranean Keto and Moroccan Keto: two flavor-rich ways to cook low-carb.

Sources and further reading

• U.S. Department of Agriculture, FoodData Central: https://fdc.nal.usda.gov
• U.S. Food and Drug Administration, "How to Understand and Use the Nutrition Facts Label": https://www.fda.gov
• Mifflin MD, et al. "A new predictive equation for resting energy expenditure in healthy individuals." American Journal of Clinical Nutrition, 1990.

This guide is for educational purposes only and does not replace professional medical advice.