Estimate how much muscle mass you can build naturally with four recognized models: Lyle McDonald, Martin Berkhan, Alan Aragon and Casey Butt. See your genetic ceiling and how much room you still have to grow.
It is the muscle ceiling your body can reach without ergogenic substances. This calculator uses four scientific models (McDonald, Berkhan, Aragon and Casey Butt) to give you a realistic range based on genetics and bone structure.
Measure wrist circumference above the wrist bone (narrowest point) and ankle circumference above the ankle bone (narrowest point). If you do not enter them, average values are used.
If you do not know your body fat percentage, estimate visually (men: 10-25%, women: 18-35% are typical ranges). Years training refers to serious, consistent weight training.
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Maximum muscle mass is the total amount of muscle a person can develop without ergogenic substances. It depends on genetic factors such as bone structure, natural hormone levels and response to training.
This calculator combines four recognized scientific models to give you a realistic range. Each model approaches the question from a different angle: yearly gains, height proportions, rates relative to body weight and bone measurements.
The Casey Butt model is especially useful because it includes wrist and ankle circumferences, which are direct indicators of individual bone structure. This allows a more personalized prediction than models based only on height and weight.
Knowing your maximum muscle mass limit helps you set realistic goals, adjust training and nutrition plans, and avoid comparing yourself to unrealistic social media standards.