Carbs in Watermelon: The Quick Answer
Watermelon contains 7.1g of net carbs per 100g, calculated by subtracting 0.4g of dietary fiber from 7.5g of total carbohydrates. With 30.0 calories, 0.6g protein, and 0.1g fat per 100g, it is classified as Low Carb 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 Watermelon Keto Friendly?
Watermelon is low carb with 7.1g net carbs per 100g and can be eaten in moderate amounts on keto. Keep portion size in mind and track it against your daily carb limit.
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 Watermelon: 7.5g − 0.4g = 7.1g 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.