Lean Body Mass Calculator
Enter your sex, height, and weight to instantly calculate your lean body mass using the Boer formula.
Use the Lean Body Mass Calculator
Your Measurements
Enter your measurements and click Calculate to see your lean body mass.
Your Lean Body Mass
--
kg
--
lb
Body Composition Breakdown
Lean mass --
Body fat --
Total Weight
--
Lean Mass
--
Est. Fat Mass
--
Formula used (Boer, 1984):
Copied to clipboard!
Summary
Lean body mass (LBM) is the weight of everything in your body except fat — muscles, bones, organs, and fluids. This calculator uses the Boer formula, which is considered more accurate than older methods like the James or Hume formulas because it was derived from a larger, more diverse population. Results are available in both metric (kg) and imperial (lb) units.
How it works
- Select your biological sex (male or female).
- Enter your height in centimeters or feet and inches.
- Enter your weight in kilograms or pounds.
- The Boer formula computes lean body mass instantly.
- View your LBM in both kg and lb, plus your estimated body fat percentage range.
Use cases
- Set personalized protein intake targets based on muscle mass.
- Track body composition changes over a fitness program.
- Help healthcare providers estimate drug dosing by lean mass.
- Compare LBM before and after a bulk or cut cycle.
- Estimate caloric needs more accurately than total weight alone.
- Understand how muscle-to-fat ratio affects athletic performance.
Frequently Asked Questions
Last updated: 2026-05-23 · Reviewed by Nham Vu