Lean Body Mass for 80 kg, 175 cm, Male
Estimated lean body mass and fat mass for 80 kg, 175 cm, Male, using three widely used medical formulas. Adjust any field below to personalize the result.
Lean Body Mass
149.8 lbs
67.9 kg — average of 3 formulas
Fat Mass
26.6 lbs
12.1 kg — 15.1% of total weight
For a 80.0 kg male, the average of three lean body mass formulas is approximately 149.8 lbs (67.9 kg) of lean mass — about 15.1% estimated body fat.
Total body weight, split between lean mass and fat mass
- Lean Mass: 149.8 lbs
- Fat Mass: 26.6 lbs
Formula Comparison
| Formula | LBM (lbs) | LBM (kg) | Published |
|---|---|---|---|
| Boer (most used) | 132.5 | 60.1 | 1984 |
| James | 193.3 | 87.7 | 1976 |
| Hume | 123.7 | 56.1 | 1966 |
What is a Lean Body Mass Calculator?
A lean body mass (LBM) calculator estimates the portion of your total body weight that isn't fat — muscle, bone, organs, water, and connective tissue. Unlike body fat percentage (which starts from a direct or estimated fat measurement), lean body mass formulas were built to predict a "fat-free" reference weight from just height, weight, and gender, originally for clinical drug dosing.
LBM is widely used by athletes and bodybuilders to track muscle gain independent of fat loss or gain, and by clinicians to dose medications (especially anesthesia and chemotherapy) more precisely than total body weight allows, since drug distribution correlates more closely with lean tissue than with fat.
The Three Lean Body Mass Formulas
All three formulas below take height, weight, and gender as inputs and output an estimated lean mass in kilograms. They were derived from different reference populations and use different mathematical shapes, which is why this calculator shows all three rather than picking a single "correct" answer.
Hume's 1966 formula was the first widely adopted LBM equation, developed for estimating creatinine excretion. Boer's 1984 formula is now the most commonly cited and used in clinical dosing calculators due to its simplicity and broad validation. James's 1976 formula uses a different mathematical shape (a squared ratio term) and tends to diverge more at higher body weights.
Lean Body Mass vs. Body Fat Percentage
These two metrics describe the same underlying reality from opposite directions. Body fat percentage is usually measured or estimated directly (skinfold calipers, bioelectrical impedance, DEXA scans) and lean mass is calculated as whatever remains. LBM formulas work the other way: they estimate lean mass directly from height and weight, then imply a fat mass and body fat percentage as the remainder. Because LBM formulas don't measure your actual body composition, they can be meaningfully wrong for people who fall outside the average build the formulas were calibrated on — see the FAQ below.
If you have a body fat percentage measurement from a scale, calipers, or scan, you can calculate lean mass directly as Weight × (1 − Body Fat %) — a more personalized figure than any height/weight formula can provide. For a direct body fat estimate, try the Body Fat Calculator.
Why Athletes Track Lean Body Mass
Total body weight alone can't distinguish between gaining muscle and gaining fat — the scale moves the same way either direction. Tracking an LBM estimate alongside body weight over weeks or months gives a rough signal of whether weight changes are coming from muscle or fat, which is exactly what matters during a bulking or cutting phase. That said, height/weight-based LBM formulas are fairly insensitive to short-term changes — a DEXA scan or repeated skinfold measurements will track real muscle gain far more precisely than recalculating these formulas week to week.
Example — Your Current Inputs
For a 80.0 kg male, the average of three lean body mass formulas is approximately 149.8 lbs (67.9 kg) of lean mass — about 15.1% estimated body fat.
Additional Example — 5'6" Female
A 5'6" (168 cm), 140 lb (63.5 kg) female: Boer estimates about 45.6 kg (100.5 lbs) lean mass; James about 44.9 kg (99.0 lbs); Hume about 45.2 kg (99.6 lbs) — a tight spread of under 2 lbs across all three formulas. The average, about 45.2 kg (99.7 lbs) of lean mass, implies roughly 40.3 lbs of fat mass, or about 28.8% estimated body fat.
About These Parameters
- Height and Weight
- Every formula here uses only height, weight, and gender — no body fat measurement is required. This makes the calculator quick to use but also means it can't account for your actual muscle-to-fat ratio the way a direct body composition measurement would.
- Gender
- Every formula uses different constants for males and females, reflecting that males typically carry a higher proportion of lean mass at the same height and weight — driven mainly by higher average muscle mass and bone density, and lower average essential fat percentage.
Frequently Asked Questions
Which lean body mass formula is most accurate?
Boer's 1984 formula is the most widely used in clinical settings today and generally tracks closely with James and Hume for people of average build. None of the three is definitively "correct" for every individual — they were all derived from population averages, not from measuring your specific body composition. Treat the spread across all three as a reasonable estimate range rather than a precise figure.
Why do these formulas overestimate lean mass for very overweight or obese people?
All three formulas were derived and validated primarily on people of average to moderately overweight build. At higher body weights, a growing share of extra weight is fat rather than lean tissue, but these linear/near-linear formulas keep scaling upward with total weight, so they can overstate lean mass (and understate body fat percentage) for people with obesity. A direct body composition measurement is considerably more reliable at higher body weights.
Is lean body mass the same as muscle mass?
No. Lean body mass includes muscle, but also bone, organs, connective tissue, and body water — muscle typically makes up roughly 40–50% of total lean mass in a healthy adult. So an increase in lean body mass isn't purely a muscle gain; it can also reflect changes in hydration or, less commonly, bone density.
How is lean body mass used for medication dosing?
Certain medications — notably many anesthetics and chemotherapy agents — distribute through the body in proportion to lean tissue rather than total body weight, since fat tissue has relatively poor blood supply. Dosing by total body weight can lead to overdosing in patients with a higher body fat percentage. Clinicians use LBM-based dosing (often with the Boer formula specifically) to estimate a safer, more effective dose for these medications.