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Lean Body Mass Calculator

Health & Body

Boer & James formulas for lean mass and fat mass

Quick Answer

Lean Body Mass Calculator: Boer & James formulas for lean mass and fat mass. Boer: male LBM = 0.407W + 0.267H − 19.2; female LBM = 0.252W + 0.473H − 48.3.

Lean body mass (avg of 3 formulas)

57.2 kg

Est. fat mass 17.8 kg → implied body fat 23.8%

Boer58.0 kg
James59.0 kg
Hume54.4 kg
Fat mass17.8 kg

Body composition

Lean mass57kg (76.3%)Fat mass18kg (23.7%)

Steps (Boer)

  1. 1LBM = 0.407×75 + 0.267×175 − 19.2 = 58.0 kg
  2. 2James/Hume give 59.0/54.4 kg; averaged = 57.2 kg
  3. 3Fat = 75 − 57.2 = 17.8 kg (23.8%)

💡 LBM = everything except fat (muscle, bone, water, organs). It's the basis for drug dosing, protein targets (1.6-2.2 g/kg LBM for athletes), and resting metabolism. The "implied body fat" here is a population-average estimate — muscular individuals will read higher than reality. For accuracy use DEXA or impedance scales.

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How to Use

  1. Enter body metrics: fill height, weight, age etc. as prompted by the Lean Body Mass Calculator.
  2. Read value and grade: results appear instantly with an authority-based classification.
  3. Check reference tables: confirm your range and healthy targets against the tables on this page.
  4. Back-solve your goal: adjust inputs to see what it takes to reach a target.

Key Points

  • Lean Body Mass Calculator is a free online health tool — open and use, no sign-up.
  • All calculations run locally in your browser; your data never leaves the device.
  • Key capability: Boer & James formulas for lean mass and fat mass.
  • Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

Lean body mass formulas

Boer: male LBM = 0.407W + 0.267H − 19.2; female LBM = 0.252W + 0.473H − 48.3
James: male LBM = 1.1W − 128(W/H)²; female LBM = 1.07W − 148(W/H)²
Fat mass = weight − LBM
Both formulas usually agree; average them, or use a body-fat scale

Example: male 75 kg, 175 cm → Boer ≈ 58.0 kg, James ≈ 57.3 kg, avg ≈ 57.7 kg, fat ≈ 17.3 kg.

FAQ

How do I use the Lean Body Mass Calculator?
Open the page and fill in the input fields — results update automatically. Boer & James formulas for lean mass and fat mass.
Are the results accurate?
Results follow published international standards (WHO, ACE, IOM) and are for reference only.
Can this replace medical advice?
No. Always consult a qualified healthcare professional for health decisions.
Is it free? Do I need to sign up?
Completely free. No registration, login or download required.
Does it work on mobile?
Yes. The responsive design works on all devices.

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Source & Updates

Based on WHO, ACE, IOM and other published international standards. Last updated: 2025-07

Authoritative sources:

Last updated:

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Maintained and periodically reviewed by the YiJianSuan editorial team — review process in ourEditorial Policy.

Cite this page: YiJianSuan. Lean Body Mass Calculator[EB/OL]. https://www.yijiansuan.com/en/c/health/lean-body-mass

Results provided by this tool are for reference only and do not constitute professional advice.