Lean Body Mass Calculator
Calculate your lean body mass using the Boer formula.
📐 Boer Formula — Men: 0.407×Weight + 0.267×Height − 19.2 · Women: 0.252×Weight + 0.473×Height − 48.3
Lean body mass (LBM) is the weight of everything in your body except fat — muscle, bone, water, organs, and connective tissue. It is a critical metric for athletes, fitness enthusiasts, and clinicians because it determines metabolic rate, strength potential, and overall health trajectory. Higher lean mass means higher resting metabolism, better insulin sensitivity, and greater functional capacity as you age. This calculator uses the Boer formula to estimate lean body mass from height, weight, and sex.
📋 How to Use This Calculator
Enter your sex, weight in kg, and height in cm. Click Calculate to see your estimated lean body mass, fat mass, and body fat percentage. You can also compare with ideal lean mass ranges for your height. If you have access to a body fat measurement (from DEXA, calipers, or Navy method), enter it to calculate lean mass directly: LBM = Total weight × (1 − body fat%).
💡 Key Facts & Information
Boer formula for LBM: Men: LBM = 0.407 × weight(kg) + 0.267 × height(cm) − 19.2. Women: LBM = 0.252 × weight(kg) + 0.473 × height(cm) − 48.3. Typical body composition: athletic men (LBM 85–90% of body weight), athletic women (LBM 75–85%). Average sedentary adults: men 75–80% LBM, women 65–75% LBM. Muscle loss with age: sarcopenia begins around age 30 and progresses at 3–5% per decade without resistance training. By age 70, untrained individuals may have lost 30% of their peak muscle mass. Resistance training 2–3 times per week can largely prevent age-related muscle loss and maintain metabolic rate. LBM directly determines your Basal Metabolic Rate — each kg of muscle burns approximately 13 kcal/day at rest.