Lean Body Mass Calculator

Calculate your Lean Body Mass (LBM) using the Boer Formula.

Introduction

Welcome to the Lean Body Mass Calculator! This tool estimates your Lean Body Mass (LBM), which is the weight of your body excluding fat (muscle, bones, organs, etc.), using the Boer Formula. You can input your height and weight in various units, and optionally estimate your body fat percentage by providing your total body weight. LBM is useful for fitness planning, nutrition, and understanding body composition.

Height Unit:

Height:

Height (Inches):

Height (Centimeters):

Height (Meters):

Weight Unit:

Weight:

Gender:

How to Use

Select your height unit (feet/inches, inches, centimeters, or meters) and enter your height.
Select your weight unit (pounds or kilograms) and enter your weight.
Select your gender (male or female).
Click "Calculate" to see your Lean Body Mass in both kilograms and pounds, along with an estimated body fat percentage.
Click "Save Calculation" to store your results locally.
Use "Reset" to clear all inputs and start over.

Understanding Lean Body Mass

What is Lean Body Mass?

Lean Body Mass (LBM) is the weight of your body excluding fat. It includes muscles, bones, organs, and water. Knowing your LBM can help with fitness planning, nutrition, and understanding your body composition.

How We Calculate

We use the Boer Formula to estimate LBM, with height in centimeters and weight in kilograms:
- Men: LBM (kg) = 0.407 × weight (kg) + 0.267 × height (cm) - 19.2
- Women: LBM (kg) = 0.252 × weight (kg) + 0.473 × height (cm) - 48.3
The result is shown in both kilograms and pounds (1 kg = 2.20462 lbs).
Body fat percentage is estimated as: [(Total Weight - LBM) ÷ Total Weight] × 100.

Unit Conversions

The calculator converts your inputs to the units required by the Boer Formula (height in cm, weight in kg):
- Height: 1 foot = 12 inches, 1 inch = 2.54 cm, 1 meter = 100 cm
- Weight: 1 lb = 0.453592 kg, 1 kg = 2.20462 lbs

Using Your LBM

Your LBM can help you:
- Determine your protein needs (e.g., 1.6-2.2 g of protein per kg of LBM for muscle building).
- Estimate your Basal Metabolic Rate (BMR) more accurately, as LBM is a key factor in metabolism.
- Track changes in body composition during fitness or weight loss programs.

Limitations

The Boer Formula provides an estimate and may not be accurate for everyone, especially those with very high muscle mass or atypical body compositions. For precise measurements, consider methods like DEXA scans or hydrostatic weighing.

FAQs

What’s the difference between LBM and muscle mass?

LBM includes all non-fat tissues (muscles, bones, organs, water), while muscle mass refers only to skeletal muscle. LBM is a broader measure of your body’s lean components.

Why is my body fat percentage estimate inaccurate?

The body fat percentage is a rough estimate based on the difference between your total weight and LBM. If your weight input isn’t accurate or the Boer Formula doesn’t fit your body composition, the estimate may be off.

Can I use this calculator if I’m very muscular?

Yes, but the Boer Formula may underestimate LBM for highly muscular individuals. Consider a more advanced method for accuracy.

About This Calculator

Built by xAI, this Lean Body Mass Calculator uses the Boer Formula to estimate your LBM, with support for multiple units. For personalized fitness advice, consult a trainer or healthcare provider.