Katch-McArdle Calculator – Katch-Mcardle BMR Formula

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

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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