Lean Body Mass Calculator: Boer, James and Hume Formulas
Health & fitnessFreeNo sign-up
Lean body mass is your weight minus fat mass. A 180 lb man who is 70 inches tall has about 134 lb of lean mass by the Boer, James and Hume formulas.
A man weighing 180 lb and 70 inches tall has an estimated lean body mass of about 133.7 lb, based on the average of the Boer, James and Hume formulas. That leaves about 46.3 lb of fat mass, or 26% of body weight.
Show the steps
- Weight 81.6 kg, height 177.8 cm.
- Boer: 0.407 × weight + 0.267 × height − 19.2 = 61.5 kg.
- James: 1.1 × weight − 128 × (weight ÷ height)² = 62.8 kg.
- Hume: 0.3281 × weight + 0.33929 × height − 29.5336 = 57.6 kg.
Lean body mass formulas (kg, cm)
Boer (men): 0.407 W + 0.267 H − 19.2; (women): 0.252 W + 0.473 H − 48.3
James (men): 1.1 W − 128 (W ÷ H)²; (women): 1.07 W − 148 (W ÷ H)²
Hume (men): 0.3281 W + 0.33929 H − 29.5336; (women): 0.29569 W + 0.41813 H − 43.2933
- These formulas estimate lean mass from height and weight. They do not see how muscular you are, so measured body composition is more accurate.
- This is general information, not medical advice.
Estimates for planning and learning, not financial, tax, legal or medical advice. Check figures with your lender, tax preparer or doctor before you act.
About this calculator
Lean body mass includes muscle, bone, organs and water, but not fat. Doctors use it to dose some medicines, and athletes use it to track muscle gain.
This calculator applies three published formulas and shows each result, plus the average. If you know your body fat from a scan or caliper test, enter it in the options for a direct calculation.
How to use it
- Choose your units and sex.
- Enter your weight and height.
- Optionally enter a measured body fat percentage.
- Read the lean mass from each formula and the average.
The formulas
Boer, James and Hume each fit height and weight to measured lean mass. They give similar answers for average builds but differ for very lean, muscular or heavy people, which is why the average is shown.
Using the result
Lean mass is a better guide than weight for protein needs and for tracking whether weight loss comes from fat or muscle. For best accuracy use a DEXA scan.
Sources
Quick check: test yourself
What is lean body mass?
Correct answer: Total weight minus fat mass. Lean mass includes muscle, bone, organs and water.
A person weighs 180 lb with 20% body fat. Their lean mass is…
Correct answer: 144 lb. 180 × (1 − 0.20) = 144.
Which formulas does this calculator average?
Correct answer: Boer, James and Hume. It averages three commonly used lean body mass formulas.
Pick an answer for each question.
Common questions
What is lean body mass?
Everything in your body except fat: muscle, bone, organs, skin and water.
How is lean body mass calculated?
By subtracting fat mass from weight, or by a formula using height and weight, such as Boer, James or Hume.
Is lean body mass the same as muscle mass?
No. Muscle is only part of it.
How accurate are these formulas?
They are estimates. A DEXA scan or other body composition test is more accurate.
More health & fitness calculators
Related to This Article
More math articles
- Algebra Puzzle – Challenge 39
- Consensus and polarization
- FREE 3rd Grade MAP Math Practice Test
- Visualizing Multiplication: How to Use Arrays to Multiply Fractions by Whole Numbers
- Day of the Week Calculator
- Age Calculator
- The Best Grade 4 Math Book for Idaho Students
- How to Graph Rational Expressions? (+FREE Worksheet!)
- The Best Grade 7 Math Book for Nebraska Students
- The Best Grade 3 ELA Practice Tests for Pennsylvania Students
What people say about "Lean Body Mass Calculator: Boer, James and Hume Formulas - Effortless Math"?
No one replied yet.