Katch-McArdle Formula
The gold-standard metabolic equation that calculates BMR directly from Lean Body Mass, ignoring biological sex and age.
Clinical & Bioenergetic Overview
Formulated by Frank Katch and William McArdle, this equation isolates metabolically active Lean Body Mass (LBM) to determine resting energy expenditure. Because internal organs and skeletal muscle tissue drive resting metabolism while adipose tissue is relatively inert, isolating LBM yields exceptional accuracy for muscular athletes and lean trainees.
Mathematical Formula & Calculation
Real-World Worked Example
A male weighing 90 kg with 12% body fat has 79.2 kg of lean mass. BMR = 370 + (21.6 × 79.2) = 370 + 1,710.7 = 2,081 kcal/day.
Why It Matters for Dieting
Provides far more accurate targets for bodybuilders and strength competitors whose muscularity exceeds population averages.
Frequent Mistakes
Entering an inaccurate body fat percentage. If body fat is guessed via visual estimation, the resulting BMR calculation may be skewed.
Calculate with Katch-McArdle
Enter your body fat percentage to unlock lean mass precision.
Related Bioenergetic Terms
The total mass of your body minus all extractable storage adipose tissue.
The proportion of total body weight composed of adipose tissue relative to overall mass.
The validated clinical formula developed in 1990 used to predict Basal Metabolic Rate from height, weight, age, and sex.