Health⏱ 6 min read
How to Calculate Macros for Muscle Gain (Bulking)
Building muscle requires a calorie surplus and sufficient protein — but the exact numbers depend on your body weight, training intensity, and how fast you want to gain. Here's the complete formula.
Muscle gain requires two things: a calorie surplus (eating more than maintenance) and enough protein to provide building blocks for new tissue. Getting the numbers right makes the difference between an efficient bulk and gaining mostly fat.
Step 1: Calculate Your Maintenance Calories (TDEE)
TDEE = BMR × Activity Multiplier
BMR (Mifflin-St Jeor, male):
= (10 × kg) + (6.25 × cm) − (5 × age) + 5
Example: 25-year-old male, 80kg, 178cm, training 4× per week
BMR = (10×80) + (6.25×178) − (5×25) + 5
= 800 + 1,112.5 − 125 + 5 = 1,792.5
Activity multiplier (moderately active / 3–5 days): 1.55
TDEE = 1,792.5 × 1.55 = 2,778 calories/day
Step 2: Set Your Surplus
Lean bulk (minimise fat gain): +200–300 calories above TDEE
Standard bulk: +300–500 calories above TDEE
Aggressive bulk: +500–700 calories above TDEE
Recommendation: start with +300 cal for most people.
Adjust based on weekly weight change:
Target rate of muscle gain:
Beginners: 0.5–1.0 kg/month possible
Intermediate: 0.25–0.5 kg/month realistic
Advanced: 0.1–0.25 kg/month
Weekly weight should increase by ~0.1–0.25 kg/week
If gaining faster → too much surplus, gaining fat
If not gaining → increase by 100–150 cal
Step 3: Set Protein
Optimal protein for muscle gain:
1.6–2.2g per kg of body weight per day
Practical target: 2g/kg/day (easy to remember, well within optimal)
Example: 80kg lifter
Protein target = 80 × 2 = 160g/day
Calories from protein = 160 × 4 = 640 cal
Step 4: Set Fat (Floor)
Fat minimum for hormonal health (testosterone, etc.):
0.7–1.0g per kg of body weight
Example: 80kg
Fat minimum = 80 × 0.8 = 64g/day
Calories from fat = 64 × 9 = 576 cal
Step 5: Fill the Rest with Carbohydrates
Remaining calories after protein and fat = carbohydrate calories
Total target calories: 2,778 + 300 = 3,078 cal
Protein calories: 640 cal
Fat calories: 576 cal
Remaining for carbs: 3,078 − 640 − 576 = 1,862 cal
Carb grams: 1,862 ÷ 4 = 465g/day
Full Macro Summary
MacroGramsCalories% of Total
Protein160g64021%
Fat64g57619%
Carbohydrates465g1,86060%
Total3,076100%
Timing and Distribution
Spreading protein evenly across 3–5 meals maximises muscle protein synthesis (MPS). Research suggests each meal should contain at least 20–40g of protein to maximally stimulate MPS. Eating 160g spread across four meals (40g each) is more effective than two meals of 80g.
Post-workout nutrition matters — consuming 30–40g protein within 2 hours of training supports recovery — but the total daily amount is more important than precise timing for most people.