Work out calorie from macronutrients instantly with clear inputs, formula shown and shareable results.
Labelling energy uses the Atwater factors: 4 kcal per gram for protein and available carbohydrate, 9 for fat and 2 for dietary fibre. One kilocalorie is 4.184 kilojoules. Percentage of energy from fat matters for nutrient claims, since many thresholds are set on energy share rather than gram content.
Energy calculation
kcal = protein x 4 + fat x 9 + carbohydrate x 4 + fibre x 2
Kilojoules
kJ = kcal x 4.184
Nutrition labelling energy factors and rounding rules are set by regulation and differ between jurisdictions. Confirm the rules applicable to your market.
Yes — 2.4 kcal/g for polyols, 7 kcal/g for ethanol, 3 kcal/g for erythritol in some jurisdictions and 0 in others. Check the applicable labelling regulation.
Some fibre is fermented in the colon to short-chain fatty acids that are absorbed. Regulations vary: 2 kcal/g in the EU, 4 kcal/g in the US where fibre is included in total carbohydrate.