Calculate your lean body mass
Enter your details below. The Boer formula estimates your lean body mass from height, weight and sex. No account, no signup.
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What is lean body mass?
Lean body mass (LBM) is everything in your body except fat: muscle, bones, water, organs and connective tissue. It is the "engine" of your body — the more lean mass you carry, the more calories you burn at rest. Two people can weigh the same but look completely different depending on how much of that weight is lean mass.
This calculator uses the Boer formula:
Men: (0.407 × weight in kg) + (0.267 × height in cm) − 19.2
Women: (0.252 × weight in kg) + (0.473 × height in cm) − 48.3
Worked example: A man, 75 kg, 175 cm: 0.407×75 + 0.267×175 − 19.2 = 30.525 + 46.725 − 19.2 = 58.0 kg lean body mass. Body fat ≈ (75 − 58.0) ÷ 75 × 100 = 22.6%.
Next: find your protein needs → — protein is the key nutrient for building and keeping lean mass.
Frequently Asked Questions
What is lean body mass? Lean body mass is everything in your body except fat — muscle, bones, water, organs and connective tissue. The more lean mass you have, the more calories you burn at rest.
Is lean body mass the same as muscle mass? Not exactly. Muscle mass is the weight of your muscles only. Lean body mass includes muscle plus bones, water, organs and connective tissue. Muscle is the largest part of lean body mass, but not the whole thing.
How accurate is the Boer formula? It is a widely used estimate based on height, weight and sex. It is close to lab measurements for most people, but less accurate for very muscular athletes, people with a lot of body fat, or unusual body proportions. A DEXA scan is the most accurate way to measure lean body mass.
How can I increase my lean body mass? Strength training 2–4 times a week plus enough protein (roughly 1.6–2.2 grams per kilogram of body weight per day for active people) is the proven way to build lean mass. Consistency over months matters more than any single workout or meal.
Is this medical advice? No. This is general information only. Talk to a doctor or registered dietitian before changing your diet or training, especially if you have a health condition.