Carbs in Tomato: The Quick Answer
Tomato contains 2.8g of net carbs per 100g, calculated by subtracting 1.2g of dietary fiber from 4.0g of total carbohydrates. With 20.0 calories, 0.8g protein, and 0.3g fat per 100g, it is classified as Keto Friendly for carbohydrate content.
Net carbs — not total carbs — are what matter for keto and low-carb diets. Only net carbs raise blood sugar and affect insulin, which is why tracking them accurately is key to staying in ketosis. Use our Keto Macro Calculator to find your daily net carb limit based on your body and goals.
Is Tomato Keto Friendly?
Tomato is keto friendly with only 2.8g net carbs per 100g. It fits comfortably within the standard keto limit of 20–50g net carbs per day and can be included regularly on a ketogenic diet.
How Net Carbs Are Calculated
Net carbs are calculated by subtracting dietary fiber (and sugar alcohols, if present) from total carbohydrates: Net Carbs = Total Carbs − Fiber. For Tomato: 4.0g − 1.2g = 2.8g net carbs per 100g.
Dietary fiber is subtracted because it passes through the digestive system without being absorbed as glucose. It does not raise blood sugar or trigger an insulin response, making it irrelevant for carb counting on keto and low-carb diets.