Lean Body Mass Calculator.

Formula or algorithm and variables.

Equation, units, and population

Boer: male set LBM = 0.407W + 0.267H − 19.2; female set LBM = 0.252W + 0.473H − 48.3. W is weight in kilograms and H is height in centimetres. The sex parameter selects the published equation coefficients. This page names the equation rather than presenting an unexplained score. Check that every value uses the displayed unit and that you belong to the population for which the method is described. The calculation retains full precision internally and rounds only the visible result. A reproducible estimate should let another reader use the same inputs and reach the same arithmetic answer, while still recognizing that mathematical reproducibility does not prove medical suitability.

Worked example

For a 70 kg, 175 cm adult using the female coefficient set, the Boer equation estimates 52.1 kg lean body mass, about 74.5% of total weight. Work through the example by writing the equation, substituting each labeled input, and preserving units at every step. The example demonstrates arithmetic only; it is not a recommended body measurement, intake, exercise level, laboratory value, or date. Replace every example input with the values from the situation being considered, and retain those inputs with any result you copy. Small differences can arise from rounding, equation versions, atomic-weight conventions, or date boundaries.

Interpreting the estimate

Lean body mass includes water, organs, bone, and muscle. It is not synonymous with muscle mass, and small changes in an estimate may reflect input or formula variation rather than real tissue change. Health calculations compress complex biology into a few inputs, so the result should be read as context rather than a verdict. Do not compare two people as though the higher or lower number is automatically better. Look for changes over time only when the method, units, and conditions are consistent. If a result conflicts with symptoms, a laboratory report, a clinician’s instructions, or a validated measurement, rely on the appropriate professional evidence rather than this calculator.

Validation and edge cases

Weight must be 30–300 kg and height 120–230 cm. Nonfinite values and estimates outside zero to total body weight are rejected. Blank, malformed, nonfinite, and out-of-domain inputs fail explicitly without producing NaN or infinity. The bounds prevent obviously implausible values from being mistaken for meaningful answers, but passing a range check does not make an input medically correct. Recheck dates, decimal separators, unit conversions, coefficient choices, and whether a laboratory value uses the expected assay and unit. Contact a qualified professional when a result could affect treatment, medication, pregnancy care, nutrition therapy, or exercise safety.

Limitations and responsible use

Population equations can be inaccurate for athletes, older adults, adolescents, pregnancy, edema, amputation, unusual body composition, or people outside the development population. This equation estimates lean mass; it does not measure body fat or diagnose nutrition, fitness, or health. FigureNest processes these inputs locally in the browser and does not send them to a calculation service. The page does not create a medical record, assess symptoms, or know personal history. Avoid using estimates to shame a body, pursue unsafe restriction, delay care, determine legal fitness, or replace contraception. Authoritative source links are provided so readers can check the equation version and current guidance before making a consequential decision.

Check assumptions and sources.

Population equations can be inaccurate for athletes, older adults, adolescents, pregnancy, edema, amputation, unusual body composition, or people outside the development population.

CDC Adult BMI Categories