How macro percentages become grams: divide energy by 4 or 9
Carbohydrate, protein and fat provide different amounts of energy per gram. Equal energy percentages therefore do not imply equal weights.
Macro calculator →Work through a 2000 kcal allocation
Suppose carbohydrate receives 50%, protein 20% and fat 30%, totaling 100%. Carbohydrate receives 1000 kcal, which divided by 4 gives 250 g. Protein receives 400 kcal, giving 100 g. Fat receives 600 kcal, which divided by 9 gives about 66.7 g. This is an arithmetic example, not a universal dietary recommendation.
Distinguish energy share from weight share
The three amounts total roughly 416.7 g. Fat contributes about 16% of that mass, even though it contributes 30% of the energy. The original percentages refer to energy, not grams. Confusing those definitions is a common reason a food record seems inconsistent. Always label a percentage with the quantity it describes.
Check the inputs before using the output
The three input percentages must add to 100. Establish an appropriate energy total separately; the calculator cannot determine whether a nutrient target suits a particular person. Foods also contain water, fibre and other components, so these macro grams are not the weight of a complete meal. The calorie and percentage tools help check the calculation without turning it into a personalized nutrition prescription.
Try the calculators
- Macro calculator
Convert daily calories into carbohydrate, protein and fat grams.
- Calorie calculator
Estimate maintenance energy for your activity level.
- Percentage calculator
Find a percentage of any number.