Katch-McArdle Calculator
Calculate your Basal Metabolic Rate (BMR) using lean body mass for precise metabolic assessment
Calculate Your BMR with Katch-McArdle Equation
Your body weight minus fat mass (from DEXA, BodPod, or hydrostatic weighing)
BMR Results
Formula: BMR = 370 + (21.6 × Lean Body Mass in kg)
Calculation: BMR = 370 + (21.6 × 0.0) = 0 kcal/day
Example Calculation
Athletic Male Example
Age: 25 years old
Weight: 80 kg (176 lbs)
Height: 180 cm (5'11")
Body Fat: 12%
Lean Body Mass: 80 × (100 - 12) / 100 = 70.4 kg
Katch-McArdle Calculation
BMR = 370 + (21.6 × 70.4)
BMR = 370 + 1,520.64
BMR = 1,891 kcal/day
This is higher than Harris-Benedict estimates due to higher muscle mass
Body Composition Methods
DEXA Scan
Most accurate (±1-2%)
Gold standard for body composition
BodPod
Very accurate (±2-3%)
Air displacement plethysmography
Skinfold Calipers
Moderate accuracy (±3-5%)
Requires skilled technician
Bioelectrical Impedance
Variable accuracy (±5-8%)
Affected by hydration status
Katch-McArdle Tips
Most accurate for lean individuals with known body composition
Accounts for muscle mass differences between individuals
Best for athletes and bodybuilders
Single equation for both males and females
Requires accurate body composition data
Understanding the Katch-McArdle Equation
What is the Katch-McArdle Formula?
The Katch-McArdle formula calculates Basal Metabolic Rate (BMR) based on lean body mass rather than total body weight. This makes it more accurate for individuals with known body composition, particularly those with higher muscle mass.
Why is it More Accurate?
- •Muscle tissue burns more calories than fat tissue
- •Accounts for individual differences in body composition
- •More precise for athletes and fitness enthusiasts
- •Single equation works for both sexes
Formula Explanation
BMR = 370 + (21.6 × LBM in kg)
- BMR: Basal Metabolic Rate (kcal/day)
- 370: Base metabolic constant
- 21.6: Metabolic factor per kg of lean mass
- LBM: Lean Body Mass in kilograms
Note: This formula requires accurate body composition data for optimal results.
Comparison with Other BMR Formulas
| Formula | Required Data | Best For | Accuracy |
|---|---|---|---|
| Katch-McArdle | Lean body mass | Athletes, known body fat % | Highest for lean individuals |
| Mifflin-St Jeor | Age, weight, height, sex | General population | Good for most people |
| Harris-Benedict | Age, weight, height, sex | Historical reference | Tends to overestimate |
Medical Disclaimer
This calculator provides estimates for educational purposes only. BMR calculations are approximations and individual metabolic rates can vary significantly. For medical advice, weight management, or specific health concerns, consult with a healthcare professional, registered dietitian, or certified fitness expert. This tool should not replace professional medical assessment or personalized nutrition advice.