Macro calculator
Calculate your daily protein, carbohydrate and fat targets based on your goal.
PhD Sports Science, Registered Nutritionist (RNutr)
Sports scientist and registered nutritionist specialising in metabolic health, athletic performance and dietary analysis.
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About the Macro calculator
Macronutrients — protein, carbohydrates, and fat — are the three classes of nutrients that provide calories. Understanding how to apportion them within your calorie target is the foundation of evidence-based nutrition, sometimes called "IIFYM" (If It Fits Your Macros). While total calories ultimately determine whether you gain or lose weight, the macro split determines body composition: whether you're losing fat or muscle, or gaining muscle or fat.
Protein is the most critical macro to "anchor" first, especially during any phase involving body composition change. Each gram of protein provides 4 calories and supplies amino acids for muscle protein synthesis. Research consistently shows that 1.6–2.2 g of protein per kg of body weight maximises muscle retention during caloric deficit and muscle growth during surplus. Higher intakes (up to 3 g/kg) are safe and may provide modest additional benefit for very experienced trainees.
After protein is anchored, fat and carbohydrate targets are set from the remaining calories. Fat provides 9 calories per gram — more than double protein or carbs — and is essential for hormone production, fat-soluble vitamin absorption, and cell membrane integrity. A minimum of around 0.5–0.6 g/kg body weight (approximately 20–25% of calories) is generally recommended. Carbohydrates provide 4 calories per gram and are the primary fuel for high-intensity exercise. The more active you are, the higher your carbohydrate allocation should be.
How it works
Protein (g) = body_weight_kg × protein_multiplier Fat loss: 2.0 g/kg Maintain: 1.8 g/kg Muscle gain: 2.2 g/kg Protein calories = protein_g × 4 Fat calories = total_calories × fat_percentage Fat (g) = fat_calories ÷ 9 Carb calories = total_calories − protein_calories − fat_calories Carbohydrates (g) = carb_calories ÷ 4
Where
4 kcal/gCalories per gram of protein and carbohydrate9 kcal/gCalories per gram of dietary fat1.6–2.2 g/kgEvidence-based protein target range per kg of body weightWorked example
80 kg male, fat loss goal, 2,300 kcal target
Protein: 80 kg × 2.0 g/kg = 160 g
Protein calories: 160 × 4 = 640 kcal
Fat: 30% × 2,300 = 690 kcal
Fat grams: 690 ÷ 9 = 77 g
Carbs: 2,300 − 640 − 690 = 970 kcal
Carb grams: 970 ÷ 4 = 243 g
Final split: 160g P / 243g C / 77g F
Tips to improve your result
- 1.
Protein is the most important macro to hit consistently. When calorie restricted, muscle protein synthesis becomes rate-limited by leucine availability — protein keeps muscle-building processes running.
- 2.
Spreading protein across 3–5 meals with 30–50 g per meal is more effective for muscle protein synthesis than eating it all at once. The "leucine threshold" per meal is approximately 2–3 g of leucine, found in around 20–30 g of whey protein or 40–50 g of meat/fish.
- 3.
Dietary fat is not uniquely fattening — it provides 9 kcal/g and can exceed calorie targets easily, but it does not directly cause fat gain more than any other calorie source. Unsaturated fats (olive oil, avocado, nuts, oily fish) are preferable for cardiovascular health.
- 4.
Carbohydrates directly fuel muscle glycogen during resistance training and cardio. Athletes and highly active individuals typically benefit from higher carb intakes (40–50%+ of calories), while more sedentary individuals may do well with lower carbs.
- 5.
Alcohol provides 7 kcal/g and is not a macronutrient — but it contributes significantly to calorie totals and disrupts muscle protein synthesis and fat metabolism.