Macro calculator (carbs, protein and fat)
Split your daily calories into grams of carbs, protein and fat based on your diet.
Carbs and protein have 4 kcal/g; fat, 9 kcal/g. Set calories from your needs (use the BMR calculator).
How the calculation works
"Macros" are the three energy-providing macronutrients: carbs, protein and fat. The idea is to split your daily calories among them by your chosen diet.
The key step converts a percentage of calories into grams, and each macro has a different energy density:
- Carbs: 4 kcal per gram
- Protein: 4 kcal per gram
- Fat: 9 kcal per gram
grams = (total calories × macro %) ÷ kcal per gram
Step-by-step example (2,000 kcal, 40/30/30)
- Carbs (40%): 800 kcal ÷ 4 = 200 g
- Protein (30%): 600 kcal ÷ 4 = 150 g
- Fat (30%): 600 kcal ÷ 9 ≈ 67 g
Why fat yields fewer grams
Since each gram of fat has more than double the calories, the same 30% becomes far fewer grams than carbs. That's why small amounts of oil, nuts and cheese weigh heavily on the total.
Examples
- 2,000 kcal 40/30/30: 200 g carbs, 150 g protein, 67 g fat.
- Low-carb 20/40/40 at 1,800 kcal: 90 g carbs, 180 g protein, 80 g fat.
Frequently asked questions
How many calories should I eat?
Use the BMR/TDEE calculator to find your total, then adjust for your goal.
What is the best macro split?
It depends on your goal and preference. A balanced 40/30/30 works for most; low-carb raises fat and protein. Total calories matter more than the exact split.
Do I need to hit macros exactly?
No. They are reference targets; being close by day's end is fine. Prioritize protein, most linked to satiety and muscle.
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See all →Updated on June 18, 2026 · by Rafael Rossi · Methodology & sources