Lean Body Mass Calculator
Use this Lean Body Mass Calculator to estimate your fat-free body weight based on your gender, height, and body weight. It gives you a practical lean mass estimate in kilograms and pounds with a clear formula-based breakdown.
Select your gender, choose your preferred unit system, and enter your height and weight. The calculator uses the Boer formula to estimate lean body mass and shows your result in both kg and lb.
How to Use This Lean Body Mass Calculator
Choose your gender and preferred unit system first. Then enter your weight and height and click the calculate button. The tool converts imperial measurements into metric values when needed and applies the Boer formula automatically.
You can use the result as a practical reference for body composition tracking, calorie planning, and fitness goal setting.
What Is Lean Body Mass?
Lean body mass is the part of your total body weight that does not come from body fat. It includes muscle, bones, organs, body water, and other fat-free tissues.
This number helps you understand body composition better because scale weight alone does not show how much of your body weight comes from lean tissue and how much comes from fat.
Why Use Our Lean Body Mass Calculator?
- Estimate fat-free body weight quickly
- Support calorie and macro planning
- Track body composition with better context
- Review weight changes more clearly
- Use a simple calculator on mobile and desktop
Lean Body Mass Formula Used
This calculator uses the Boer formula, which is a recognized method for estimating lean body mass from height, weight, and gender.
For men
Lean Body Mass = (0.407 × weight in kg) + (0.267 × height in cm) − 19.2
For women
Lean Body Mass = (0.252 × weight in kg) + (0.473 × height in cm) − 48.3
How This Lean Body Mass Calculator Works
The calculator reads your gender, body weight, and height, then converts your data into metric units if you use imperial measurements. After that, it applies the Boer formula and shows your estimated lean body mass in both kilograms and pounds.
This result is formula-based, so it works best as a practical estimate rather than an exact medical measurement.
Lean Body Mass Calculation Example
Example: A man who weighs 70 kg and has a height of 175 cm can use the Boer formula for men.
Lean Body Mass = (0.407 × 70) + (0.267 × 175) − 19.2
Lean Body Mass = 28.49 + 46.725 − 19.2 = 56.015 kg
So the estimated lean body mass is about 56.0 kg, which is roughly 123.5 lb.
Lean Body Mass vs Muscle Mass
Lean body mass is not the same as muscle mass. Muscle mass is only one part of lean body mass. Lean body mass also includes bones, organs, water, and other fat-free tissues.
This is why lean body mass usually appears higher than muscle mass alone.
Why Lean Body Mass Matters
Lean body mass matters because it gives you a more useful view of body composition than body weight alone. Two people can weigh the same, but one may carry more muscle while the other carries more body fat.
Many people use lean body mass estimates to guide protein intake, calorie targets, cutting phases, maintenance planning, and strength-focused fitness goals.