📊 Compare Genetic Potential Models
Compare different natural muscle-building potential prediction models side-by-side. Enter your measurements once and see how Casey Butt, Lyle McDonald, FFMI, and Alan Aragon models predict your maximum natural physique.
Compare all major genetic potential models in one place. Each model uses different methodologies to predict your maximum drug-free muscle mass, and the results can vary significantly. This tool lets you see all predictions simultaneously to understand your natural ceiling from multiple perspectives.
Enter your measurements below to generate personalized predictions from Casey Butt's Frame Size Model, Lyle McDonald's Height/Weight Method, FFMI Natural Limits, and Alan Aragon's Rate-Based progression.
🧮 Enter Your Measurements
Your Genetic Potential Comparison
Detailed Model Comparison
| Model | Predicted Weight | Lean Mass | FFMI | Timeline |
|---|---|---|---|---|
| Casey Butt | - | - | - | 8-12 years |
| Lyle McDonald | - | - | - | 8-12 years |
| FFMI 25 Ceiling | - | - | 25.0 | 8-12 years |
| Alan Aragon (5 years) | - | - | - | 5 years |
📊 Understanding Your Results
Calculate your measurements to see personalized analysis of how different models predict your natural potential.
✅ Model Consensus
Average Prediction: - kg at contest condition
Range: - kg
Recommendation: Use the average as your realistic target. All models assume 8-12 years of optimal training.
Understanding Each Model
1. Casey Butt Frame Size Model
Methodology: Uses wrist and ankle circumference as indicators of skeletal robustness. Analyzed 300+ champion natural bodybuilders.
Formula: LBM = H1.5 × (√W/22.667 + √A/17.010) / 3.5
Strengths: Most detailed; accounts for bone structure; provides body-part-specific predictions
Limitations: Most conservative; requires accurate wrist/ankle measurements
2. Lyle McDonald Height/Weight Method
Methodology: Simple height-to-weight ratio based on natural competitive bodybuilders.
Formula: Contest Weight (kg) = Height (cm) - 100
Strengths: Simplest formula; easy to remember; moderate predictions
Limitations: Doesn't account for frame size; assumes average bone structure
3. FFMI Natural Ceiling
Methodology: Based on Kouri et al. (1995) research distinguishing natural from enhanced athletes.
Limit: FFMI 25 (adjusted) for natural males; FFMI 20 for females
Strengths: Research-validated; peer-reviewed; height-adjusted
Limitations: Provides ceiling, not personalized prediction; sensitive to BF% accuracy
4. Alan Aragon Rate-Based Model
Methodology: Monthly muscle gain rates based on training experience.
Rates: Beginner (1-1.5% BW/month) → Intermediate (0.5-1%) → Advanced (0.25-0.5%)
Strengths: Practical for progress tracking; adjusts to current weight; experience-based
Limitations: Doesn't predict ultimate ceiling; requires self-assessment
🧬 Try Individual Calculators
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