Using the Macro Calculator
Enter protein and fat as percentages of total calories, not percentages of food weight. Carbohydrate receives the remainder. For example, 25% protein and 30% fat leave 45% for carbohydrate. Protein and fat cannot add to more than 100%, because that would leave a negative carbohydrate allocation.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Daily calories (kcal)
- 2000
- Protein (%)
- 25
- Fat (%)
- 30
Example result
- Protein (g/day)
- 125
- Fat (g/day)
- 66.666667
- Carbohydrate (g/day)
- 225
Method and assumptions
Uses 4 kcal/g for protein and carbohydrate, 9 kcal/g for fat. This converts your chosen targets rather than prescribing a diet.
Keep the food quantity consistent
Nutrition arithmetic depends on the quantity of food being described. A per-serving value and a per-hundred-gram value cannot be added or compared directly without scaling them first. When checking a food diary, confirm that all entries use the amount actually recorded. These conversions explain numbers; they do not assess whether a diet meets an individual's needs.
Common question
Why does fat have fewer grams for the same calories?
The calculation uses 9 kilocalories per gram of fat, compared with 4 per gram of protein or carbohydrate. A calorie percentage therefore describes an energy share, not an equal share of grams or an equal portion of the plate.
Guide updated .