Nutritional Information Calculator
Calculate total calories and macronutrients for any portion size based on label data.
How to Use the Nutritional Information Calculator
Managing your diet requires precision. Most food packaging provides nutritional data based on 100g portions, but we rarely eat exactly 100g. This calculator bridges that gap by scaling macronutrients to your specific serving size.
Understanding the 4-4-9 Rule
The total calorie count is derived from the Atwater system, which assigns energy values to macronutrients:
- Protein: 4 calories per gram.
- Carbohydrates: 4 calories per gram.
- Fats: 9 calories per gram.
Example Calculation: Chicken Breast
If you have 250g of cooked chicken breast, and the label says that per 100g it contains 31g of Protein and 3.6g of Fat:
- Protein: (31 / 100) * 250 = 77.5g
- Fat: (3.6 / 100) * 250 = 9g
- Total Calories: (77.5 * 4) + (0 * 4) + (9 * 9) = 310 + 81 = 391 kcal.
Why Accuracy Matters in Nutrition
Small errors in portion estimation can lead to significant calorie discrepancies over time. By weighing your food in grams and using this calculator, you ensure that your food diary reflects reality, making it easier to hit your weight loss or muscle gain goals.
Tips for Precise Tracking
Always weigh your food in the state you are tracking it (raw vs. cooked). Foods like pasta and rice expand significantly during cooking, while meat shrinks. If your label provides "as sold" (raw) data, weigh the ingredients before cooking for maximum accuracy.