Lean Body Mass Calculator: Your Fat-Free Body Weight
A 5'10", 175 lb male has an estimated lean body mass of approximately 143-148 lbs (Boer formula), meaning about 27-32 lbs (15-18%) is body fat. Lean mass includes muscle, bone, water, organs, and connective tissue — everything except stored fat.
Calculate Lean Body Mass
Multiple formulas compared.
Lean Body Mass (Average)
--
LBM Estimation Formulas
| Formula | Men | Women | |||
|---|---|---|---|---|---|
| Boer (1984) | LBM = 0.407W + 0.267H - 19.2 | LBM = 0.252W + 0.473H - 48.3 | |||
| James (1976) | LBM = 1.1W - 128(W/H)^2 | LBM = 1.07W - 148(W/H)^2 | |||
| Hume (1966) | LBM = 0.3281W + 0.3393H - 29.5 | LBM = 0.2958W + 0.4181H - 43.3 | (W = weight in kg, H = height in cm) Why Lean Body Mass Matters | Application | How LBM Is Used |
| Calorie needs | BMR is more accurately calculated from LBM (Katch-McArdle formula) | ||||
| Protein targets | Protein should be based on LBM, not total weight (especially for higher body fat) | ||||
| Drug dosing | Many medications are dosed based on lean body mass | ||||
| Fitness tracking | LBM increases indicate muscle gain; LBM decreases indicate muscle loss | ||||
| Anesthesia | Anesthetic dosing often uses LBM for safety | Lean Body Mass Ranges | Category | Men (% of total weight) | Women (% of total weight) |
| Athletic | 85-92% | 78-85% | |||
| Fit | 80-85% | 75-80% | |||
| Average | 75-80% | 70-75% | |||
| Overfat | 65-75% | 60-70% |
Sources
Frequently Asked Questions
What is lean body mass?
Lean body mass (LBM) is your total body weight minus all stored body fat. It includes skeletal muscle, bone, water (which makes up about 60% of LBM), organs, and connective tissue. LBM is not the same as muscle mass — muscle is a component of LBM, but LBM also includes bone, water, and organs. Typical LBM for men is 75-85% of total weight; for women, 70-80%.
How is lean body mass different from muscle mass?
Lean body mass includes everything except fat: muscle, bone, water, organs, blood, and connective tissue. Skeletal muscle typically represents about 40-50% of lean body mass in a fit individual. So if your LBM is 150 lbs, your skeletal muscle mass is roughly 60-75 lbs. DEXA scans can separate these components more precisely.
Why should I calculate protein based on lean body mass?
Body fat does not require protein for maintenance — only lean tissue does. For someone with high body fat (30%+), calculating protein based on total body weight overestimates protein needs. A 250 lb person with 35% body fat has an LBM of ~163 lbs. Protein at 1g per pound of LBM (163g) is more appropriate than 1g per pound of total weight (250g).
Can I increase my lean body mass?
Yes, primarily through resistance training and adequate protein intake. Beginners can gain 1-2 lbs of lean mass per month with proper training and nutrition. Intermediate lifters gain 0.5-1 lb per month. Advanced lifters gain 0.25-0.5 lb per month. A caloric surplus of 200-400 calories above maintenance combined with progressive resistance training optimizes lean mass gains.
How accurate are LBM formulas without body fat measurement?
Height-weight based LBM formulas (Boer, James, Hume) have a standard error of approximately 2-4 kg (4-9 lbs). They are less accurate for very lean or very obese individuals. If you know your body fat percentage (from a DEXA scan, calipers, or Navy method), a more accurate calculation is: LBM = total weight x (1 - body fat percentage/100).