Katch-McArdle Calculator

Calculate your BMR based on body composition - the most accurate method for athletes

Uses Body Fat Percentage
Most Accurate for Athletes
Body Composition Based
Gender-Neutral Formula

Enhanced BMR Calculator

Calculate your Basal Metabolic Rate with personalized insights and recommendations

Most accurate for most people

This determines your Total Daily Energy Expenditure (TDEE)

About the Katch-McArdle Formula

The Katch-McArdle formula is a unique approach to calculating Basal Metabolic Rate (BMR) that uses lean body mass instead of total body weight. This makes it the most accurate method when body fat percentage is known, as it directly accounts for the metabolic activity of muscle tissue versus fat tissue. Unlike other formulas, Katch-McArdle is gender-neutral because it focuses on body composition rather than gender-based averages. This formula is particularly valuable for athletes, bodybuilders, and anyone with unusual body composition where standard formulas may be less accurate.

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Input your weight in kilograms or pounds

💡 Why Body Composition Matters

Muscle tissue is metabolically active and burns more calories at rest than fat tissue. By accounting for body fat percentage, the Katch-McArdle formula can provide more accurate BMR estimates for individuals with atypical body compositions, such as athletes with high muscle mass or elderly individuals with sarcopenia (muscle loss).

Frequently Asked Questions

Katch-McArdle is more accurate for athletes because it accounts for their unusual body composition. Standard formulas like Mifflin-St Jeor and Harris-Benedict assume average body fat percentages, which don't apply to athletes with very high muscle mass and low body fat. By using actual body composition data, Katch-McArdle provides personalized accuracy.

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Katch-McArdle Formula Details

The mathematical formula and scientific background of the Katch-McArdle equation

Metric:BMR ​=​ 370 ​+​ ​(​21.6 ​×​ lean body mass in kg​)​ | Lean Body Mass ​=​ weight in kg ​×​ ​(​100 ​-​ body fat percentage​)​ ​÷​ 100
Imperial:For imperial units: BMR ​=​ 370 ​+​ ​(​21.6 ​×​ lean body mass in kg​)​ | Lean Body Mass ​=​ weight in kg ​×​ ​(​100 ​-​ body fat percentage​)​ ​÷​ 100

Formula

BMR ​=​ 370 ​+​ ​(​21.6 ​×​ lean body mass in kg​)​
Lean Body Mass ​=​ weight in kg ​×​ ​(​100 ​-​ body fat percentage​)​ ​÷​ 100

Scientific Background

The Katch-McArdle formula is based on the principle that metabolic rate is primarily determined by lean body mass (muscle, organs, bones) rather than total body weight. This approach recognizes that muscle tissue is metabolically active (burning approximately 13 calories per kg per day), while fat tissue is relatively metabolically inactive (burning about 4.5 calories per kg per day). The formula was developed based on research showing that lean body mass is the strongest predictor of resting metabolic rate. When body fat percentage is accurately measured, this formula can achieve accuracy rates of 95% or higher compared to metabolic testing, making it the most precise method available for BMR estimation.