Grams to Calories Converter
Convert grams of a macronutrient to Calories (kcal) using standard 4-4-9 factors, or type any custom kcal-per-gram value.
Calories (kcal)
400
Breakdown
- Factor used (kcal/g)
- 4
- Kilojoules (kJ)
- 1,673.60
Last updated:
FAQ
How do I convert grams to calories?
Multiply the grams by the energy density of the macronutrient: 4 kcal/g for carbs and protein, 9 kcal/g for fat, 7 kcal/g for pure alcohol. 100 g of fat is therefore 900 kcal.
Where do the 4-4-9 factors come from?
They are the Atwater general factors published by the USDA — the same numbers printed on every US nutrition label. Specific foods vary slightly (fiber and sugar alcohols are often counted differently), but 4/4/9 is the standard reference.
Is a Calorie the same as a kcal?
Yes. In nutrition, 1 Calorie (capital C) = 1 kilocalorie = 1000 small calories ≈ 4.184 kJ. This calculator reports nutritional Calories.
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