Net carbs are the carbohydrates your body digests and uses for energy. They equal total carbohydrates minus dietary fiber minus applicable sugar alcohols. Fiber passes through undigested; most sugar alcohols are only partially absorbed.

Why is erythritol subtracted fully but other sugar alcohols only 50%?

Erythritol is absorbed in the small intestine but excreted unchanged, so it has essentially zero metabolic impact. Other sugar alcohols (maltitol, xylitol, sorbitol) are partially fermented or absorbed, contributing roughly half the glycemic impact of regular sugar — so only half is subtracted.

Are net carbs recognized by the FDA?

No. The FDA does not officially define "net carbs." The concept is used in low-carb and ketogenic diet communities. The nutrition label shows total carbohydrates, fiber, and sugar content; net carbs is a derived figure you calculate yourself.

How many net carbs per day for ketosis?

Most strict ketogenic protocols target 20–50 g net carbs per day. Individual tolerance varies; some people stay in ketosis at 50 g while others need to stay under 20 g. Consult a dietitian for personalized guidance.

Should I count all sugar alcohols the same way?

No. Erythritol is subtracted 100%. Other sugar alcohols are estimated at 50% in the standard option because they can have a partial glycemic effect. Choose the erythritol or other-sugar-alcohol option that matches the label you are calculating.

Net Carbs Calculator

Enter total carbs, fiber, and sugar alcohols to calculate net carbs for keto and low-carb diet tracking.

Food Item

Food / Item Name (optional)

Total Carbohydrates (g) *

Dietary Fiber (g)

Sugar Alcohols (g)

Sugar Alcohol Type

Current Item

Enter carb values to see net carbs.

Meal Total

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Daily Net Carb Targets

20 g

Strict Keto

20–50 g

Standard Keto

50–100 g

Low-Carb

Summary

Enter total carbs, fiber, and sugar alcohols to calculate net carbs for keto and low-carb diet tracking.

How it works

Enter the total carbohydrates from the nutrition label.
Enter the dietary fiber content (subtract in full — fiber is not digested).
Enter any sugar alcohols (erythritol is subtracted in full; others at 50%).
The calculator instantly shows net carbs = total carbs − fiber − adjusted sugar alcohols.
Add multiple food items to calculate net carbs for an entire meal.
Reset or remove individual items to adjust your meal list.

Use cases

Track daily net carb intake on a ketogenic diet.
Compare net carbs in packaged foods before buying.
Calculate net carbs for a full meal or recipe.
Determine whether a sugar-free product fits your carb budget.
Teach yourself how fiber and sugar alcohols affect carb counts.
Plan meals within a specific net carb target (e.g., 20 g/day for strict keto).

Frequently Asked Questions

Last updated: 2026-09-19 · Reviewed by Nham Vu