Build Muscle &
Gain
Mass
Calculate the optimal calorie surplus to maximize muscle growth while minimizing fat gain.
01. Stats
02. Measurements
03. Activity
Bulking requires energy. Ensure you fuel your workouts.
Calories to maintain your current physique.
Growth Fact
Muscle grows best in a caloric surplus. Aim for 0.25-0.5% body weight gain per week.
To gain weight, you must eat more than you burn. Choose a surplus strategy below that fits your goals.
Choose Your Surplus
Lean Bulk
Minimize fat gain
Standard Bulk
Max muscle potential
Dirty Bulk
Maximum size (and fat)
Ready to Grow?
Enter your stats to find your bulking numbers.
Mechanisms of Hypertrophy
Muscle growth, or skeletal muscle hypertrophy, is an adaptation to stress. It occurs when muscle fibers sustain trauma (like lifting weights) and the body repairs them to be larger and stronger than before. This process is driven by Muscle Protein Synthesis (MPS).
To build muscle, MPS must exceed Muscle Protein Breakdown (MPB). This requires two key inputs: adequate amino acids (protein) and sufficient energy (calories). Without a calorie surplus, your body prioritizes energy maintenance over expensive tissue building.
Training Volume & Intensity
Calories alone won't build muscle—they will just be stored as fat. You must provide a stimulus.
Drivers of Growth:
- Mechanical Tension: Lifting heavy weights through a full range of motion.
- Metabolic Stress: The "pump" or burning sensation from high-repetition work.
- Progressive Overload: Consistently adding weight, reps, or sets over time.
Clean vs. Dirty Bulking
The old school "Dirty Bulk" method suggests eating everything in sight to maximize size. However, the human body has a limit to how much muscle it can synthesize in a day—roughly 25-50 calories worth of new tissue for a novice male.
Eating 1000 calories over maintenance doesn't triple your muscle growth; it simply ensures you gain 900 calories of body fat.
The Modern Approach (Lean Bulk): A small surplus of 200-300 kcal provides enough energy for maximum MPS without excessive fat gain. This allows you to stay in a building phase for months without needing to cut aggressively.
Reality Check: How Fast Can You Grow?
Beginner
1.0 - 1.5% body weight per month.
(Newbie Gains)
Intermediate
0.5 - 1.0% body weight per month.
(Need Structure)
Advanced
0.25 - 0.5% body weight per month.
(Hard Gained)
Based on the Lyle McDonald genetic potential model.
Nutrient Timing: Does it Matter?
For bulking, TOTAL daily intake remains king, but timing plays a supportive role:
- Pre-Workout: Carbs fuel intense sessions (e.g., Oatmeal, Fruit).
- Post-Workout: Protein + Carbs spike insulin to shuttle nutrients into depleted muscles.
- Before Bed: Slow-digesting protein (Casein) keeps MPS elevated overnight.