Net Carbs Calculator for Keto & Low-Carb Diets

Imagine this: John has just started the keto diet. He’s motivated and at the grocery store, reading a snack label. It says:

• Total Carbohydrates: 30g
  
• Dietary Fiber: 12g
  
• Sugar Alcohol: 4g
  

John frowns. “Do I have to count all 30 grams? Or is it less?”

This confusion is exactly why the Net Carbs Calculator exists. It takes the numbers on a food label and shows you the true carbs that affect your blood sugar and ketosis.

What is a Net Carbs Calculator?

A Net Carbs Calculator is a simple but essential tool for people following a keto or low-carb lifestyle.

• Total carbs include everything: sugar, fiber, starch, and sugar alcohols.
  
• Fiber is not digested by the body, so it doesn’t raise blood sugar.
  
• Most sugar alcohols have little to no effect on blood glucose.
  

By subtracting the parts of carbs that don’t count, the calculator tells you the net carbs — the carbs your body actually uses for energy and the number that decides whether you stay in ketosis.

Formula for Net Carbs

Here’s the straightforward formula:

Net Carbs = Total Carbohydrates – Dietary Fiber – Sugar Alcohols

👉 Example with John’s snack:
30g total carbs – 12g fiber – 4g sugar alcohol = 14g net carbs

That’s the number that matters for keto.

• Erythritol: Subtract 100% (doesn’t raise blood sugar).
  
• Maltitol: Subtract only half (it can spike glucose).
  
• Xylitol & Sorbitol: Have moderate effects, so use caution.
  

How the Calculator Works – Step by Step

1. Look at your food label and note the Total Carbs, Fiber, and Sugar Alcohols.
   
2. Enter the values into the calculator.
   
3. The tool instantly applies the formula.
   
4. You see the net carbs result — the number that counts toward your daily target.
   
5. Compare it with your daily limit (most keto dieters stay under 20–50g net carbs per day).
   

That’s it. Instead of doing the math in your head every time, the calculator saves you from mistakes and confusion.