πŸ’ͺIdeal Muscle Mass Target Calculator

Calculate ideal target muscle mass from height, weight, and skeletal frame.

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How to Calculate Your Ideal Muscle Mass Target

This calculator applies Martin Berkhan's natural lean body mass formula, which is based on FFMI (Fat Free Mass Index) research. For men, the baseline target is height (cm) minus 100, adjusted by skeletal frame size (Β±2–5 kg). Women's targets are approximately 60–65% of the male equivalent.

Current muscle mass is estimated from your lean body mass (weight Γ— (1 – body fat fraction)), with approximately 65% attributed to skeletal muscle. The remainder accounts for bone, organ mass, and water. For accurate measurements, a DEXA scan or professional BIA device is recommended.

Natural muscle gain rates: beginners can expect 8–12 kg/year, intermediates 2–4 kg/year, and advanced lifters 1–2 kg/year. These estimates assume consistent training and adequate protein intake (1.6–2.2 g/kg/day).

Frequently Asked Questions

What is FFMI and why does it matter?

FFMI (Fat Free Mass Index) = lean body mass (kg) Γ· heightΒ² (mΒ²). The natural maximum FFMI is approximately 25 for men and 22 for women. Values above these are generally associated with performance-enhancing drug use.

How do I determine my skeletal frame size?

Measure your wrist circumference. For men: under 6 inches (15.2 cm) = small, 6–7 inches = medium, over 7 inches (17.8 cm) = large. For women: under 5.5 inches = small, 5.5–5.75 inches = medium, over 5.75 inches = large.