Lean Body Mass Calculator: Track Your Body Composition

The scale definitely doesn't tell the whole story! This calculator shows you how your weight breaks down into fat mass and lean mass, so you can know how effective your diet and training are.

Lean Body Mass Calculator: Track Your Body Composition banner

"Lean body mass" may sound like the amount of muscle you have, but that's not quite true. More accurately, it's the amount of weight you carry that isn't body fat. Your LBM includes muscle, but also bones, water, connective tissue, and stored up glycogen and other substances.

This calculator requires two inputs from you: your total body weight and body-fat percentage. This can help you track whether the weight you gain or lose is coming in the form of fat or from LBM. Once you know that, you can make more informed nutrition and training choices to nail your fitness and physique goals.

Lean Body Mass Calculator

Body Fat Percentage

Now that you know how your body weight breaks down into fat mass and lean mass, here are your next steps:

1. Pick a workout plan.

Following a well-designed lifting program is the best way to increase your lean body mass, often while decreasing your body fat. Here are some of the most popular ones from BodyFit:

2. Calculate your macros.

Eating adequate protein is a proven way to increase lean body mass, and muscle mass in particular. The Bodybuilding.com Macronutrient Calculator will give you a daily target for not only protein, but also carbohydrates, dietary fats, and calories.

3. Learn about the best supplements for gaining muscle.

Supplements can help you accelerate your lean-mass-building results once you have your protein intake and training nailed down. Krissy Kendall, Ph.D., shares her recommendations in the article, "8 Proven Supplements for Muscle Growth and Strength."

4. Join a fitness community.

For over 10 years, members of BodySpace have been helping each other build their best bodies. Join the world's strongest fitness community!

Why Is Lean Body Mass Important?

Knowing your balance of lean and fat mass is a better indicator of your overall body composition than the scale alone—even assuming that your scale is accurate. Likewise, body mass index (BMI) charts are problematic because they often erroneously list muscular individuals as obese, even when they have a low body-fat percentage.

You can also use your lean body mass as a benchmark for assessing progress so you can fine-tune your macronutrients to build muscle. Certain training programs, like Layne Norton's PH3: 13-Week Power and Hypertrophy Plan use it in determining how many grams of protein you need to maintain and build muscle.

Get Systematic About Your Results

Once you know your lean body mass breakdown, it's time to take the same kind of strategic approach to the rest of your training and nutrition. These popular calculators can help you dial in your plan!