Net carbs are total carbohydrates minus fiber and often sugar alcohols. Keto and low-carb diets use them to track daily carb intake.

Is this medical advice?

No. These calculators provide estimates for education only. Work with your healthcare provider — especially if you have diabetes, take insulin, or manage blood pressure medications.

How long should I fast?

Dr. Mindy Pelz starts most people at 13–16 hours. Autophagy benefits increase around 17 hours. Extended 24–72 hour fasts need medical awareness — especially on medications.

Which calculator should I use first?

Use the net carb calculator when reading a food label. Use the macro calculator for daily targets. Use the fasting clock when you are ready to track fasts after low-carb eating feels stable.

Insulin resistance · 6 min read

How to Read Nutrition Labels for Net Carbs

Find total carbs, fiber, and sugar alcohols on US labels — step-by-step for keto and low-carb shopping.

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Net carb calculator →

Label lines to find

Net carbs ≈ total carbs − fiber − sugar alcohols. Enter numbers in our calculator for instant results.

Total Carbohydrate (top line)
Dietary Fiber (indented below — subtract fully)
Sugar Alcohols (if listed — often subtract fully for erythritol)
Serving size — multiply if you eat more than one serving

Frequently asked questions

Do I subtract all fiber?

On US labels, dietary fiber is subtracted from total carbs for net carb counting on most keto plans. Soluble fiber still has minimal impact for some people.

Insulin resistance

Net Carbs for Insulin Resistance — How Many Per Day?

How to calculate net carbs from food labels and choose daily targets for blood-sugar-friendly eating and metabolic health.

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Getting Started with Keto and Low Carb — First 2 Weeks

A practical starter plan: cut sugar first, target net carbs, prioritize protein, and when to add fasting.

8 min read

Metabolic Low Carb Calculator provides educational content only — not medical advice, diagnosis, or treatment. Talk to your healthcare provider before changing diet, fasting, or medications. Read disclaimer