About 4.0 grams. According to the daily diet, the carbohydrate content in each100g tomato is about 4.0g. Tomato is a low-calorie food. Every 100g tomato contains 20 calories, including 4.0g carbohydrate, 0.9g protein, 0.2g fat and 0.5g dietary fiber. Although the carbohydrate content in tomatoes is not high, excessive consumption may weaken the digestion and absorption ability of gastrointestinal tract. Therefore, we should control the intake of tomatoes in our daily life.