Advanced BMR Calculator

Calculate your Basal Metabolic Rate with precision and get personalized nutrition recommendations

Calculate Your BMR

Mifflin-St Jeor
Harris-Benedict
Katch-McArdle

Your Results

Fill in your details and click 'Calculate BMR' to see your personalized results

Understanding BMR & Metabolism

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic functions like breathing, cell production, and heart function while at rest. It represents the minimum amount of energy needed to keep your body functioning.

Factors Affecting BMR

  • Age: BMR decreases with age
  • Body Composition: Higher muscle mass increases BMR
  • Sex: Males generally have higher BMR than females
  • Genetics: Can influence your baseline metabolism
  • Hormones: Thyroid and other hormonal factors affect BMR

For most accurate BMR assessment, consult with healthcare professionals who can perform direct measurements.

Once you know your BMR, you can use it in conjunction with other tools like the Daily Calorie Needs Calculator to estimate your total daily energy expenditure (TDEE) and the Macro Distribution Calculator to plan your macronutrient intake for optimal health and fitness goals.

BMR Formula Comparison

This calculator uses three different formulas to estimate your BMR:

Mifflin-St Jeor

Considered the most accurate for most people. Takes into account weight, height, age, and sex.

Harris-Benedict

The original BMR formula, revised in 1984. Still widely used in nutritional settings.

Katch-McArdle

Incorporates body fat percentage for potentially more accurate results if you know your body composition.

How to Calculate Basal Metabolic Rate (BMR)

The Basal Metabolic Rate (BMR) is calculated using mathematical formulas that take into account various factors such as age, weight, height, sex, and sometimes body fat percentage. These formulas provide an estimate of the calories your body needs to maintain basic physiological functions while at rest.

Factors Affecting BMR

Popular BMR Formulas

There are several formulas used to calculate BMR, each with its own strengths and applications. Below are the most widely used BMR formulas:

Mifflin-St Jeor Formula

This formula is considered the most accurate for most people and is widely used in modern nutrition. It takes into account weight, height, age, and sex.

  • For Men: BMR = 10 × weight (kg) + 6.25 × height (cm) - 5 × age (years) + 5
  • For Women: BMR = 10 × weight (kg) + 6.25 × height (cm) - 5 × age (years) - 161

Harris-Benedict Formula

One of the earliest BMR formulas, revised in 1984. While less accurate than Mifflin-St Jeor, it is still commonly used.

  • For Men: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)
  • For Women: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age in years)

Katch-McArdle Formula

This formula is unique because it incorporates body fat percentage, making it ideal for individuals who know their body composition. It is gender-neutral.

  • BMR = 370 + (21.6 × Lean Body Mass in kg)
  • Note: Lean Body Mass = Weight (kg) × (1 - Body Fat Percentage)

Choosing the Right Formula

The choice of formula depends on the information available and the accuracy required:

Why Calculate BMR?

Calculating your BMR is essential for understanding how many calories your body needs daily. Once you know your BMR, you can combine it with your activity level to estimate your Total Daily Energy Expenditure (TDEE). This helps you create a calorie deficit for weight loss or a surplus for weight gain, depending on your goals.