Casey Butt anthropometric model

Heuristic estimates of mass and girths from height, wrist, ankle and assumed body fat. The original girths describe male bodybuilders at about 8–10% fat. Berkhan: separate reference of height (cm) − 100 kg.

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Calculation

Measure wrist and ankle snugly with a flexible tape over skeletal landmarks without compressing soft tissue.

Result

Estimated fat-free mass
80.8 kg

The male sample does not establish female norms. The model does not measure genetics, prove a muscular ceiling or predict time to achievement. Selected body fat is an assumption, not a recommended target.

Estimated weight at assumed body fat
89.8 kg

The male sample does not establish female norms. The model does not measure genetics, prove a muscular ceiling or predict time to achievement. Selected body fat is an assumption, not a recommended target.

Berkhan Contest Weight (shredded, ~5% body fat)
78.0 kg

Martin Berkhan formula: Height (cm) − 100 at extreme contest conditioning

Estimated chest girth
119.4 cm
Estimated upper arm girth
43.1 cm
Estimated forearm girth
34.4 cm
Estimated thigh girth
63.3 cm
Estimated calf girth
42.5 cm

The male sample does not establish female norms. The model does not measure genetics, prove a muscular ceiling or predict time to achievement. Selected body fat is an assumption, not a recommended target.

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How it is calculated

Heuristic estimates of mass and girths from height, wrist, ankle and assumed body fat. The original girths describe male bodybuilders at about 8–10% fat. Berkhan: separate reference of height (cm) − 100 kg.

Formula

Max LBM = Height^1.5 × [sqrt(Wrist)/22.6670 + sqrt(Ankle)/17.0104] × [(BodyFat%/224) + 1]; Berkhan Contest Weight (~5% BF) = Height (cm) − 100.

Limits of the method

The male sample does not establish female norms. The model does not measure genetics, prove a muscular ceiling or predict time to achievement. Selected body fat is an assumption, not a recommended target.

Sources of the method

This calculation is for reference only and is not medical advice, a diagnosis or a prescription. If you have a medical condition, are pregnant, take medication or have any doubts, discuss the result with a physician or a qualified nutrition professional.

How to use the calculation

1

Enter the starting values

Heuristic estimates of mass and girths from height, wrist, ankle and assumed body fat. The original girths describe male bodybuilders at about 8–10% fat. Berkhan: separate reference of height (cm) − 100 kg.

2

Adjust the parameters

Max LBM = Height^1.5 × [sqrt(Wrist)/22.6670 + sqrt(Ankle)/17.0104] × [(BodyFat%/224) + 1]; Berkhan Contest Weight (~5% BF) = Height (cm) − 100.

3

Read the result

The male sample does not establish female norms. The model does not measure genetics, prove a muscular ceiling or predict time to achievement. Selected body fat is an assumption, not a recommended target.

Frequently asked questions

What does the calculation show?

Heuristic estimates of mass and girths from height, wrist, ankle and assumed body fat. The original girths describe male bodybuilders at about 8–10% fat. Berkhan: separate reference of height (cm) − 100 kg.

What limitations apply?

The male sample does not establish female norms. The model does not measure genetics, prove a muscular ceiling or predict time to achievement. Selected body fat is an assumption, not a recommended target.

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What next

Formula breakdowns, biomarker reference ranges and nutrition articles with cited sources are in the NutriFit knowledge base.

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