Calorie From Macronutrients Calculator

Work out calorie from macronutrients instantly with clear inputs, formula shown and shareable results.

About Calorie From Macronutrients Calculator

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.

Formulas

Energy calculation

kcal = protein x 4 + fat x 9 + carbohydrate x 4 + fibre x 2

Kilojoules

kJ = kcal x 4.184

Worked example

With the default values below, Calorie From Macronutrients Calculator returns Energy Per 100 g of 400.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Proteinminimum 0 g per 100 g: 12 g per 100 g
Fatminimum 0 g per 100 g: 18 g per 100 g
Available Carbohydrateminimum 0 g per 100 g: 45 g per 100 g
Dietary Fibreminimum 0 g per 100 g: 5 g per 100 g

Results

Energy Per 100 g: 400.000
Energy In Kilojoules: 1,673.60
Energy From Fat: 40.500%
Energy From Carbohydrate: 45.000%

Step by step

1Values used
2Energy calculation
3Kilojoules
4Energy Per 100 g= 400.000
5Energy In Kilojoules= 1,673.60
6Energy From Fat= 40.500
7Energy From Carbohydrate= 45.000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Nutrition labelling energy factors and rounding rules are set by regulation and differ between jurisdictions. Confirm the rules applicable to your market.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Nutrition labelling energy factors and rounding rules are set by regulation and differ between jurisdictions. Confirm the rules applicable to your market.

Frequently Asked Questions

Do polyols and alcohol have their own factors?

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.

Why does fibre count at all?

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.