Bulking Calculator - Muscle Gain Calories
Calculate your optimal calorie surplus and macros for lean muscle gain, or track your body composition with AI-powered photo analysis.
The Science of Bulking
Muscle gain is slow, so a big surplus mostly adds fat. A 2019 review of off-season nutrition for bodybuilders in Sports recommends a surplus of about 10-20% above maintenance, aiming to gain about 0.25-0.5% of body weight per week for novice and intermediate lifters, and a more conservative approach for advanced lifters.
Optimal Surplus
Research suggests a moderate surplus maximizes muscle gain while minimizing fat accumulation
Muscle Gain Rate
Natural lifters can expect to gain 0.5-1lb of muscle per month under optimal conditions
Protein Requirements
Meta-analyses show 1.6-2.2g protein per kg bodyweight optimizes muscle protein synthesis
Bulking Calorie Calculator
Calculate Bulking Calories
Your data is not stored. This is a client-side calculation only.
Track Your Muscle Gains
See what you're actually gaining
Are you building muscle or just fat? PhysiqueAI's body scan tracks your lean mass and body fat so you know if your bulk is working.
- Track lean mass vs fat gain over time
- Weekly body composition scans
- Spot whether your surplus may be too high
- Body fat, muscle, lean and fat mass estimates
- Works with mirror selfies
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What the Research Says
Optimal Calorie Surplus for Muscle
A 2019 review in Sports (Iraki et al.) on building muscle while limiting fat gain recommends:
- A surplus of about 10-20% above maintenance
- Gaining about 0.25-0.5% of body weight per week
- Smaller surpluses for advanced lifters
Realistic Muscle Gain Rates
Muscle gain slows as you get more trained. As a general pattern (not a precise prediction for any one person):
- Beginners usually gain muscle fastest
- Gains slow down over the first few years of training
- Advanced lifters gain slowly, so a large surplus mostly adds fat
Bulking Tips for Maximum Gains
Do This
- Train hard with progressive overload
- Hit protein target daily (0.8-1g/lb)
- Sleep 7-9 hours for recovery
- Track weight weekly, adjust as needed
- Stay lean bulk if over 15% body fat
Avoid This
- Dirty bulking (excessive surplus)
- Skipping workouts while eating surplus
- Neglecting vegetables and fiber
- Bulking above 20% body fat
- Changing calories every few days
Track your bulk progress
See if your bulk is building muscle or just fat. PhysiqueAI's body scan tracks your muscle mass and body fat percentage over time.
Free account • Full results with Premium