Katch-McArdle Calculator

This page provides a Katch-McArdle calculator online, free and without any ads or distractions. This is part of a series of free nutrition tools we provide at NutriAdmin.

Explore the full range of tools on this site! You can bookmark this page and come back anytime you need to calculate nutrition-related values.

Please enter weight and body fat percentage below to calculate BMR using the Katch-McArdle Equation

Looking to calculate TDEE? Check out our TDEE calculator

What is the Katch-McArdle Equation?

The Katch-McArdle equation is a formula used to estimate Basal Metabolic Rate (BMR) by considering an individual's lean body mass (LBM), which is calculated from their body weight and body fat percentage.

Unlike other BMR formulas such as the Harris-Benedict or Mifflin-St Jeor equations, which rely on factors like age, gender, weight, and height, the Katch-McArdle equation focuses specifically on body composition.

By incorporating lean body mass, which represents metabolically active tissue like muscle, the Katch-McArdle equation provides a more personalized estimate of BMR, particularly for individuals with varying levels of muscle mass and body fat. This makes it a valuable tool for those interested in fitness, body composition, and weight management.

What is a Katch-McArdle calculator?

A Katch-McArdle calculator is a tool that allows you to calculate BMR using the Katch-McArdle formula. It requires you to provide weight and body fat percentage to determine lean body mass and BMR.

How is BMR Calculated with the Katch-McArdle Formula?

This Katch-McArdle calculator uses this formula for BMR:

BMR (kcal/day) = 370 + (21.6 × lean body mass (kg))

Where lean body mass is calculated as:

Lean Body Mass (kg) = Weight (kg) × (1 - Body Fat Percentage)

You can simply enter weight, and body fat percentage in your preferred units in the calculator above to get your result.

What is the difference between TDEE and BMR?

This page provides a Katch-McArdle calculator for BMR. BMR should not be confused with TDEE, here is a breakdown of the two and their differences.

Katch-McArdle Equation for BMR:

  • The Katch-McArdle equation estimates BMR by considering an individual's lean body mass (LBM), which is calculated from their weight and body fat percentage.
  • This equation provides a more personalized estimate of BMR, especially for individuals with varying levels of muscle mass, as it accounts for the metabolic activity of lean tissue.

Total Daily Energy Expenditure (TDEE):

  • TDEE represents the total amount of energy expended by an individual in a day, including BMR, physical activity, and the thermic effect of food.
  • Unlike BMR, which only accounts for resting metabolic rate, TDEE considers all daily activities and metabolic processes, providing a more comprehensive estimate of calorie needs.

In summary, while the Katch-McArdle equation focuses specifically on estimating BMR based on lean body mass, TDEE encompasses all aspects of energy expenditure throughout the day.

Both are important in understanding an individual's energy needs for weight management and fitness goals. BMR serves as a baseline for calorie requirements at rest, while TDEE provides a broader perspective, incorporating activity level and dietary-induced thermogenesis.

Katch-McArdle Equation Calculator BMR vs TDEE

What are the limitations of the Katch-McArdle formula?

Using a Katch-McArdle calculator is a popular alternative to Harris-Benedict for estimating BMR, but it has some limitations/drawbacks:

  • The formula relies on accurate measurement of body fat percentage, which may be challenging to obtain with precision.
  • It assumes that all weight loss is attributed to a decrease in body fat, which may not always be the case.
  • Individuals with atypical body compositions, such as athletes or those with significant muscle mass, may receive inaccurate estimates.
  • It does not account for variations in metabolic rate due to factors such as hormonal fluctuations or medical conditions.
  • The equation may not be as widely applicable or convenient as other BMR formulas that rely solely on weight and height.

What are alternatives to the Katch-McArdle Equation?

There are alternatives to using a Katch-McArdle calculator. You can estimate BMR with a couple of other formulas:

The alternatives rely on different formulas and may produce slightly different estimates.

Further information on BMR

You can read about BMR in this Wikipedia article.

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