When to use this calculator
Convert your chosen daily calorie amount and macronutrient percentages into grams of protein, carbohydrate and fat. You supply the energy amount and split; defaults are arithmetic examples, not recommended targets. Uses general 4/4/9 energy factors and does not model fibre, alcohol or individual food factors. This is not a meal plan or clinical nutrition prescription.
Explore the adult energy estimates calculators for other questions in this topic. For a related calculation, use the TDEE Calculator: Estimate adult daily maintenance calorie needs from height, weight, age and a chosen activity multiplier.
Choose percentages of energy, not percentages of food weight
Protein and carbohydrate use four kcal per gram in this general model; fat uses nine. Equal calorie shares therefore do not produce equal gram amounts. Carbohydrate is the remaining share after protein and fat, so protein plus fat cannot exceed 100%. This arithmetic does not determine a suitable diet.
PUTTING IT INTO PRACTICE
Macro: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Chosen daily energy (kcal) | 2,000 |
| Protein share (%) | 20 |
| Fat share (%) | 30 |
| Result | Protein: 100 g Carbohydrate: 250 g Fat: 66.67 g |
- Check the input labels and enter the example values above.
- Apply the relationship: Carbohydrate share = 100 − protein share − fat share; protein and carbohydrate grams = kcal share/4; fat grams = kcal share/9..
- The result is Protein: 100 g Carbohydrate: 250 g Fat: 66.67 g , rounded for display.
How to interpret your result
You supply the energy amount and split; defaults are arithmetic examples, not recommended targets. Uses general 4/4/9 energy factors and does not model fibre, alcohol or individual food factors. This is not a meal plan or clinical nutrition prescription.
Population equations and MET values are estimates rather than personal measurements. Activity multipliers can introduce substantial uncertainty. Outputs describe expenditure models, not prescribed intake, weight targets or treatment.
Frequently asked questions
Does this account for fibre or alcohol?
No. It uses the general 4/4/9 factors for the three displayed macronutrients. Fibre, alcohol, food-specific factors and nutrition-label rounding can cause differences.
Is a BMR or TDEE estimate a calorie-intake prescription?
No. It is a modelled expenditure value. It does not account for every personal or clinical factor or prescribe what an individual should eat.
When is the macro calculator useful?
Convert your chosen daily calorie amount and macronutrient percentages into grams of protein, carbohydrate and fat. You supply the energy amount and split; defaults are arithmetic examples, not recommended targets. Uses general 4/4/9 energy factors and does not model fibre, alcohol or individual food factors. This is not a meal plan or clinical nutrition prescription.
How do I use the macro calculator?
Enter chosen daily energy (kcal), protein share (%), fat share (%). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Carbohydrate share = 100 − protein share − fat share; protein and carbohydrate grams = kcal share/4; fat grams = kcal share/9..
What should I check before using the result?
You supply the energy amount and split; defaults are arithmetic examples, not recommended targets. Uses general 4/4/9 energy factors and does not model fibre, alcohol or individual food factors. This is not a meal plan or clinical nutrition prescription.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Further reading
For background on this topic, see FDA: food labelling and energy factors ↗. This is a topic reference, not an external review or endorsement of this tool.
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