What is lean body mass?

Lean body mass (LBM) is your total body weight minus fat mass. It includes muscles, bones, organs, water, and other non-fat tissue. LBM is a useful indicator of your overall body composition and muscle development.

How do I calculate lean body mass?

Lean body mass is calculated as: LBM = Total Weight x (1 - Body Fat % / 100). You need to know your body fat percentage, which can be measured with calipers, DEXA scans, or estimated using our Body Fat Calculator.

What is a good lean body mass?

Lean body mass varies greatly by gender, height, and activity level. Generally, higher lean mass relative to total weight indicates better body composition. Athletes typically have 75-90% lean mass, while average adults range from 60-80%.

How can I increase my lean body mass?

To increase lean body mass, focus on resistance training, adequate protein intake (1.6-2.2g per kg of body weight), sufficient sleep, and a slight caloric surplus. Progressive overload in strength training is key.

What is the difference between lean body mass and fat-free mass?

They are often used interchangeably, though technically lean body mass includes a small amount of essential fat (within organs and bone marrow), while fat-free mass excludes all fat. For practical purposes, the difference is negligible.

Why is lean body mass important?

LBM is important because it determines your basal metabolic rate (more muscle burns more calories), indicates physical fitness, and helps set appropriate nutrition targets. Tracking LBM over time shows whether you are gaining muscle or losing it.

Free Lean Body Mass Calculator

Calculate your lean body mass (muscle, bone, and organs) and fat mass from your weight and body fat percentage.

Calculator

Enter your weight and body fat percentage. Estimate your body fat here if unsure.

Understanding Lean Body Mass

Lean body mass (LBM) represents everything in your body that isn't fat — muscles, bones, organs, water, and connective tissue. It's a more useful measure than total weight for assessing fitness and health.

Formula

Lean Body Mass = Weight x (1 - Body Fat % / 100)

Fat Mass = Weight - Lean Body Mass

Why Lean Body Mass Matters

Higher LBM means a higher basal metabolic rate

Better indicator of fitness than weight alone

Helps set accurate protein and calorie targets

Useful for tracking body recomposition progress

Tip: Pair this calculator with the FFMI Calculator to see how your muscle mass compares relative to your height, or the Protein Calculator to set optimal protein targets based on your lean mass.

Medical Disclaimer

This calculator provides estimates based on your input. Results depend on the accuracy of your body fat percentage measurement. For precise body composition analysis, consider DEXA scanning or consultation with a healthcare provider.

Free Lean Body Mass Calculator

Understanding Lean Body Mass

Formula

Why Lean Body Mass Matters

Medical Disclaimer

Frequently Asked Questions

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Track Your Body Composition Over Time