This Katch-McArdle calculator is an advanced tool designed to estimate your Basal Metabolic Rate (BMR) with greater precision than traditional methods using Katch-McArdle equation.
The calculator was developed by researchers Frank Katch and William McArdle to provide a more accurate assessment of daily energy expenditure.
Unlike simpler calculators that only consider weight, height, age, and gender, the Katch-McArdle formula incorporates lean body mass (LBM) as its primary variable, making it particularly valuable for athletes and fitness enthusiasts.
Katch-McArdle Calculator
| Weight (lbs) | Body Fat % | LBM (kg) | BMR (calories) | Activity Level | TDEE (calories) |
|---|---|---|---|---|---|
| 150 | 15% | 57.8 | 1,618 | Moderate | 2,508 |
| 180 | 20% | 65.3 | 1,780 | Light | 2,448 |
| 200 | 25% | 68.0 | 1,839 | Very Active | 3,172 |
| 165 | 18% | 61.4 | 1,696 | Sedentary | 2,035 |
| 140 | 12% | 61.9 | 1,635 | Moderate | 2,455 |
| 175 | 22% | 68.5 | 1,795 | Light | 2,473 |
| 220 | 30% | 154.0 | 2,020 | Very Active | 3,471 |
| 160 | 25% | 120.0 | 1,740 | Moderate | 2,697 |
| 190 | 28% | 136.8 | 1,855 | Light | 2,545 |
| 210 | 24% | 159.6 | 2,032 | Very Active | 3,470 |
| 130 | 10% | 117.0 | 1,570 | Sedentary | 1,884 |
| 155 | 20% | 124.0 | 1,715 | Moderate | 2,636 |
| 185 | 27% | 135.5 | 1,850 | Light | 2,586 |
| 230 | 32% | 156.0 | 2,090 | Extremely Active | 3,951 |
Katch-McArdle Formula
The Katch-McArdle equation is expressed as:
BMR = 370 + (21.6 × Lean Body Mass in kg)Lean Body Mass (LBM) is calculated as:
Lean Body Mass = Weight × ((100 - Body Fat Percentage) / 100)BMR Calculation: Once lean body mass is known, the Katch-McArdle equation for BMR is:
BMR = 370 + (21.6 × Lean Body Mass in kg)For instance, let’s calculate the BMR for a person with:
- Total weight: 170 lbs (77.1 kg)
- Body fat percentage: 20%
First, calculate lean body mass:
- LBM = 170 lbs × (1 – 0.20) = 136 lbs
- Convert to kg: 136 lbs × 0.454 = 61.7 kg
Then apply the formula: BMR = 370 + (21.6 × 61.7) = 1,703 calories per day
How to Calculate the Katch McArdle Formula?
To accurately calculate using the Katch-McArdle formula, follow these detailed steps:
- Measure Body Fat Percentage, Use calipers, DEXA scan, Hydrostatic weighing, Bioelectrical impedance
- Calculate Lean Body Mass: Total Weight × (1 – Body Fat Percentage)
- Convert to Metric: Pounds to Kilograms (multiply by 0.454)
- Apply the Formula: Input converted LBM into the equation
- Calculate Total Daily Energy Expenditure (TDEE)
- Multiply BMR by activity factor:
- Sedentary: × 1.2
- Light Activity: × 1.375
- Moderate Activity: × 1.55
- Very Active: × 1.725
- Extremely Active: × 1.9
- Multiply BMR by activity factor:
Is Katch McArdle Accurate?
The Katch-McArdle formula is considered more accurate than other BMR formulas because it accounts for body composition.
Its accuracy depends on:
Precise Body Fat Measurements: The formula’s accuracy is directly tied to how accurately you can measure body fat percentage.
Individual Variations: Genetic factors, Hormonal balance, Medical conditions
Activity Level Assessment: Accurate selection of activity multiplier.
Research suggests it’s particularly accurate for:
- Athletes
- Bodybuilders
- Individuals with higher muscle mass
- People who regularly track their nutrition
References
- American Council on Exercise (ACE) – “https://www.acefitness.org/resources/pros/expert-articles/5008/resting-metabolic-rate-how-to-calculate-and-improve-yours/“
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