Macro Nutrient Distribution Calculator
Determine how many grams of protein, carbohydrates, and fat to eat daily based on your calorie target, body weight, goal, and diet style. Ideal for structuring a meal plan around muscle gain, fat loss, or general health.
About this calculator
Macronutrient distribution splits your daily calorie target across the three energy-providing nutrients: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). The optimal split depends on your goal and dietary approach. For muscle gain, protein is set to the higher of 2.2 g per kg of body weight or the percentage-based allocation, ensuring sufficient amino acids for muscle protein synthesis. The formula for protein grams is: protein = ROUND(goal === 'muscle_gain' ? MAX(weight × 2.2, calories × protein_ratio / 4) : calories × protein_ratio / 4). Protein ratios vary by diet type — 30% for balanced, 40% for low-carb or high-protein, and 25% for high-fat/ketogenic diets. Remaining calories are then allocated to fats and carbohydrates according to the chosen dietary framework. Getting the balance right maximises body composition changes while supporting energy, recovery, and hormonal health.
How to use
Example: 80 kg male targeting 2,500 kcal/day for muscle gain on a balanced diet (30% protein ratio). Step 1 — percentage-based protein: 2,500 × 0.30 / 4 = 187.5 g. Step 2 — weight-based protein: 80 × 2.2 = 176 g. Step 3 — take the higher value: 188 g protein (rounded). Step 4 — remaining calories: 2,500 − (188 × 4) = 1,748 kcal for carbs and fat. On a balanced split, roughly 40% carbs and 30% fat: carbs ≈ 250 g, fat ≈ 83 g. Adjust ratios using the diet type selector to match your preferred eating style.
Frequently asked questions
How much protein do I really need per day to build muscle effectively?
Research consistently supports a target of 1.6–2.2 g of protein per kg of body weight per day for maximising muscle protein synthesis in people who train regularly. The higher end (2.2 g/kg) is appropriate during a calorie deficit or for advanced lifters. Spreading protein intake across 3–5 meals of 20–40 g each optimises absorption and muscle-building signals throughout the day. Going above 2.2 g/kg provides no additional muscle-building benefit for most people, though it remains safe.
What is the best macronutrient split for fat loss without losing muscle?
A high-protein approach works best for preserving muscle during fat loss — typically 35–40% of calories from protein, 30–35% from carbohydrates, and 25–30% from fat. The elevated protein intake suppresses appetite, supports muscle retention through adequate leucine, and has a higher thermic effect than carbs or fat (meaning you burn more calories digesting it). Carbohydrate timing around workouts further helps maintain training performance while in a deficit. Avoid dropping below 0.8 g fat per kg body weight, as dietary fat supports hormone production.
Why does my protein target change depending on whether my goal is muscle gain or fat loss?
During a calorie surplus for muscle gain, additional carbohydrates and calories help spare protein for muscle building rather than energy — so the minimum effective protein dose is around 1.6–2.0 g/kg. During a deficit, the body is more likely to catabolise muscle for fuel, so protein needs to be higher (2.0–2.4 g/kg) to protect lean mass. The calculator accounts for this by applying the weight-based floor (2.2 g/kg) specifically for muscle-gain goals, ensuring you always hit a minimum threshold regardless of your calorie allocation.