How do I calculate net carbs?

Net Carbs = Total Carbohydrates − Fiber − Non-absorbed Sugar Alcohols. Fiber is fully subtracted, while sugar alcohols are partially subtracted based on their absorption rate.

Dietary fiber is not digested or absorbed for energy. It passes through the digestive system intact, so it does not contribute to the usable carbohydrate count.

Are all sugar alcohols the same?

No. Different sugar alcohols have different absorption rates. Erythritol has virtually zero impact, while maltitol is absorbed at about 67% the rate of regular sugar.

How many net carbs for keto?

Standard keto targets under 20g net carbs per day. Moderate approaches allow up to 35g, and liberal low-carb up to 50g.

Net Carbs Calculator

Name: Net Carbs Calculator
Author: Manish Kumar

Food	Serving	Total Carbs (g)	Fiber (g)	Net Carbs (g)
Avocado	1/2 medium	8.5	6.7	1.8
Spinach (raw)	2 cups	2.2	1.3	0.9
Broccoli (cooked)	1 cup	11.2	5.1	6.1
Cauliflower (cooked)	1 cup	5.3	2.9	2.4
Zucchini (cooked)	1 cup	4.8	1.5	3.3
Bell Pepper (medium)	1 medium	7.2	2.5	4.7
Mushrooms (cooked)	1 cup	8.3	3.4	4.9
Asparagus (cooked)	1 cup	7.4	3.6	3.8
Almonds	1 oz (28g)	6.1	3.5	2.6
Walnuts	1 oz (28g)	3.9	1.9	2
Chia Seeds	2 tbsp	12	10	2
Flaxseed (ground)	2 tbsp	6	5.5	0.5
Coconut (unsweetened)	2 tbsp	3	2	1
Blueberries	1/2 cup	10.7	1.8	8.9
Strawberries	1/2 cup	5.5	1.5	4
Raspberries	1/2 cup	7.3	4	3.3
Tomato (medium)	1 medium	4.8	1.5	3.3
Cucumber	1/2 medium	1.9	0.3	1.6
Green Beans (cooked)	1 cup	10	4	6
Celery	2 stalks	1.2	0.6	0.6
Dark Chocolate (85%)	1 oz (28g)	13	3.1	9.9
Peanut Butter (natural)	2 tbsp	6	2	4
Tortilla (low-carb)	1 tortilla	15	9	6
Egg (large)	1 large	0.6	0	0.6
Chicken Breast	100g	0	0	0
Salmon	100g	0	0	0
Cheese (cheddar)	1 oz	0.4	0	0.4
Cabbage (cooked)	1 cup	8.2	2.8	5.4
Kale (raw)	2 cups	5.4	1.6	3.8
Olives (black)	10 olives	3.5	1.5	2

What Are Net Carbs?

Net carbs represent the carbohydrates that are absorbed and utilized by the body for energy. The basic formula is: Net Carbs = Total Carbohydrates − Fiber − Non-absorbed Sugar Alcohols.

Dietary fiber passes through the digestive system without being broken down for energy, so it is subtracted from the total count. Sugar alcohols are partially absorbed, with different types having different impact levels.

Sugar Alcohol Impact Factors

Erythritol (0%): Virtually zero caloric impact — almost entirely excreted unchanged
Xylitol (40%): Partially absorbed with moderate impact
Sorbitol (40%): Similar absorption profile to xylitol
Isomalt (45%): Moderate absorption
Mannitol (40%): Lower absorption, similar to xylitol
Maltitol (67%): The most impactful common sugar alcohol — absorbed at about two-thirds the rate of regular sugar

When sugar alcohols are listed on a label without specifying the type, this calculator uses a 50% impact factor as a conservative middle estimate.

Reading Nutrition Labels

On US nutrition labels, dietary fiber is listed as a sub-item under "Total Carbohydrate." Sugar alcohols may or may not be listed separately. In the EU, fiber is already excluded from the carbohydrate line, so net carbs ≈ the listed carbohydrate value.

For keto-specific macro planning, use our Keto Calculator. To track all macros together, try the Carb Intake Calculator.

How to Use This Calculator

Enter total carbohydrates and fiber from the nutrition label
If the product contains sugar alcohols, enter the grams and select the type
Click "Calculate Net Carbs" to see the result with keto compatibility badge
Use "Add to Meal Builder" to track multiple foods and sum your daily net carbs
Reference the 30-food table for quick net carb lookups on common foods

Frequently Asked Questions

Sources & References

Dietary Fiber: Essential for a Balanced Approach. Anderson JW, et al.. Nutrition Reviews (2009)
Sugar Alcohols: Chemistry, Production, and Properties. Grembecka M. European Food Research and Technology (2015)

Disclaimer: This calculator is for informational and personal awareness purposes only. Results are estimates based on published formulas and may not reflect your exact measurements or outcomes.

Manish KumarNASM-CPTCertified Sports Nutritionist

Certified Personal Trainer & Sports Nutritionist

Fitness professional with 10+ years of experience in personal training, sports nutrition, and fitness technology.