Use this health-related body-size or energy equation as a screening estimate when the required measurements and demographic inputs are entered accurately.

Weight (kg)

Body weight in kilograms; must be greater than zero.

Height (m)

Height in metres; must be greater than zero.

Sex

Biological sex selecting the equation coefficients.

Compute lean body mass with the James formula from weight, height, and sex. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Lean mass (kg)

The resulting lean mass returned as a number.

• Population equations do not diagnose health or measure individual metabolism and body composition directly. Age, sex, ethnicity, muscularity, hydration, illness, medication, pregnancy, and measurement method affect interpretation.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Use trends and additional measurements rather than one number, and consult a qualified health professional when decisions involve diagnosis, treatment, or substantial weight change.

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