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Enter your values, then click Calculate result.How this calculator helps
This LBM calculator implements the specifically named Boer equation rather than treating lean mass as a measured result. Lean body mass includes more than skeletal muscle, and a height–weight expression cannot identify every body compartment independently. The page displays the coefficient choice and estimated lean share while limiting extrapolation. It is useful for reproducing a published arithmetic method or comparing estimates, with individual measurement and clinical use kept separate.
How to use it
- 1
Enter measured adult body mass in kg and height in cm.
- 2
Choose the published Boer coefficient and enter age for the disclosed adult-scope check.
- 3
Click Calculate result and review the mass and lean share.
- 4
Retain the equation label; compare with suitable independent assessment before individual interpretation.
Formula and methodology
Male coefficient: LBM kg = 0.407W + 0.267H − 19.2. Female coefficient: LBM kg = 0.252W + 0.473H − 48.3. W is body mass in kg and H is height in cm.
The calculator applies the displayed arithmetic to the values entered on this device. It does not silently load a local tax rate, currency conversion or commercial assumption.
Worked calculation example
For a 70 kg adult with height 175 cm using the male coefficient, the estimate is 0.407×70 + 0.267×175 − 19.2 = 56.015 kg. Its calculated share of body mass is 56.015/70×100, about 80.0214%. Using the female coefficient with the same measurements gives 52.115 kg. The age field checks this worksheet’s adult scope and does not appear in the Boer formula. These outputs are model estimates, not measured muscle masses.
How to interpret your result
Read the kilogram estimate and its share alongside the Boer model label. The percentage is derived from the same equation output, not an independent body-fat measurement. A result between zero and body mass satisfies a basic arithmetic constraint but cannot prove individual accuracy. Avoid relabeling the estimate as skeletal muscle or using a change between estimates as a tissue-change diagnosis.
For different inputs or formulas, use Body Fat Calculator; Resting Energy Calculator; Harris Benedict Calculator.
Related questions this calculator covers
- lbm calculator
- lean mass calculator
- lean mass weight calculator
- boer lean body mass calculator
Scenario comparison
| Scenario | What it shows |
|---|---|
| Male example | 70 kg and 175 cm gives 56.015 kg. |
| Female example | the same inputs give 52.115 kg. |
| Age scope | changing 35 to 45 does not alter the estimate, while an unsupported age is rejected. |
Common mistakes to avoid
- Calling lean mass skeletal muscle mass.
- Entering pounds or inches in metric fields.
- Treating a plausibility check as validation against an individual measurement.
Multiply each height and mass coefficient independently and check the example’s 56.015 kg. Divide by seventy and convert to a percentage. Repeat with the female coefficients. Confirm a supported age change leaves arithmetic fixed and an unsupported age blocks it. Compare the coefficient set with the linked research’s Boer expressions; measurement comparisons require an appropriate independently assessed method.
Authoritative reference. Reviewed on 6 October 2026 for the specific disclosed method or measurement context. The arithmetic is independently implemented. A linked reference does not certify an individual result or extend the worksheet beyond its stated scope.What can affect the result?
Lean mass is not skeletal muscle mass
A lean-body quantity is broader than skeletal muscle and can include organs, water, bone and other nonfat components under the intended model terminology. This calculator therefore does not target the phrase muscle mass calculator as if the two outcomes were identical. It does not measure muscle size, strength or training progress. An estimate changing with body weight is not proof that the change was muscle gain or loss.
The inputs are kilograms and centimetres
Enter measured body mass in kilograms and height in centimetres. Convert pounds or inches before entering them. The coefficients carry units implicitly, so supplying the wrong unit changes the expression rather than simply relabeling its result. The worksheet supports thirty through two hundred kilograms and one hundred forty through two hundred ten centimetres. These controls constrain extreme inputs but do not establish that every permitted combination is scientifically validated.
Coefficient sets are model choices
The published Boer expressions differ for male and female coefficient sets. The page names that selection rather than hiding it behind a generic demographic guess. A coefficient choice alone does not establish suitability for every person or clinical setting. Keep the selected model with any reported estimate. Where the model’s relevance is uncertain, a suitable body-composition assessment offers more useful evidence than selecting whichever expression gives the preferred result.
Adult age is a scope check only
The page accepts ages eighteen through sixty-five as an explicitly bounded adult worksheet. Boer’s displayed expression does not contain age, so two supported ages with identical mass, height and coefficient choice give the same estimate. The age input therefore changes eligibility, not the calculated mass within the allowed span. This distinction is disclosed to avoid implying an age sensitivity that the formula does not have. Children and out-of-scope ages are rejected rather than extrapolated.
Plausibility checks constrain extrapolation
The estimated lean mass must be positive and less than supplied total body mass. A combination that violates those conditions is rejected with a request to verify suitability and inputs. Passing the check does not validate the estimate against an individual measurement. Height–weight equations can behave poorly outside relevant populations, and a plausible-looking fraction can still have model error. Do not modify a measured weight merely to make an invalid combination return a number.
An equation is not body-composition measurement
This page does not perform DXA, bioimpedance, imaging or another measurement procedure. Those approaches have their own definitions, limitations and calibration, so they may not agree with a height–weight expression. More decimal places in the calculator cannot remove prediction error. Comparing repeated estimates can illustrate how the formula responds to mass input, but it cannot separate tissue changes or changes in hydration without independent evidence.
No dosing or nutrition prescription
Lean mass can appear in scientific and clinical calculations, but this worksheet does not convert its estimate into a medication dose, protein target or energy prescription. Such uses require method-specific suitability and clinical assessment. The linked study references the equation in a particular research context; it does not authorize applying every result to every intervention. Report the estimate as Boer LBM under the supplied inputs and retain its limitations rather than treating it as a clinical measurement.
Privacy and browser processing
Values entered on this page are processed in the current browser session. SolvePilot does not require an account and does not receive the values entered into the calculator. Refreshing or closing the page clears the working values unless the browser itself restores a previous session. Avoid entering identifying or account information because the calculation needs summary values only.
Accuracy and verification
Accuracy depends first on input quality. Confirm definitions, scales, dates and source information before entering a value. Keep an independent record of any result used for planning because this page does not create an official statement or retain a calculation history.
Limits of this estimate
Calling lean mass skeletal muscle mass. Read the kilogram estimate and its share alongside the Boer model label. The percentage is derived from the same equation output, not an independent body-fat measurement. A result between zero and body mass satisfies a basic arithmetic constraint but cannot prove individual accuracy. Avoid relabeling the estimate as skeletal muscle or using a change between estimates as a tissue-change diagnosis. Entries remain on this device for the calculation and are not submitted to a calculation server. Browser floating-point arithmetic and displayed rounding do not establish real-world measurement certainty.
Sources and review information
Frequently asked questions
Is lean body mass the same as muscle mass?＋
No. Lean mass includes additional body components beyond skeletal muscle.
Does age change the Boer arithmetic?＋
Not within the supported adult range; age is a disclosed scope check.
Can I enter pounds?＋
Convert to kilograms before entering body mass.
Why can an input combination be rejected?＋
Its estimated lean mass may not fall between zero and total mass, or it may exceed worksheet bounds.
Does this provide a medication dose?＋
No. It reports an equation estimate only.