wikiHow Converting Grams to Calories Calculator Converting grams (g) to calories (cal) is not a direct conversion because grams measure mass or weight, while calories measure energy. However, if you're looking to convert grams of a specific nutrient to calories, you can use the following conversion factors: 1 gram of carbohydrates = 4 calories 1 gram of protein = 4 calories 1 gram of fat = 9 calories To convert grams of a specific nutrient to calories, multiply the number of grams by the corresponding conversion factor. For example: Convert 50 grams of carbohydrates to calories: 50 grams * 4 calories/gram = 200 calories So, 50 grams of carbohydrates is equal to 200 calories. Convert 20 grams of protein to calories: 20 grams * 4 calories/gram = 80 calories Therefore, 20 grams of protein is equal to 80 calories. Convert 30 grams of fat to calories: 30 grams * 9 calories/gram = 270 calories Hence, 30 grams of fat is equal to 270 calories. Remember, to convert grams of a specific nutrient to calories, multiply the number of grams by the corresponding conversion factor: 4 calories/gram for carbohydrates and protein, and 9 calories/gram for fat. Page