BMR Calculator

What is BMR

Basal Metabolic Rate, also known as BMR, refers to the number of calories your body needs to maintain basic physiological functions while resting. This includes things like breathing, blood circulation, cell production, or nutrient processing.

Most of your daily calories are used for BMR, making its understanding essential for understanding the energy needs of your body. This, in turn, is useful for dieticians, medical professionals, or people who are careful about their calorie intake due to weight mitigation.

Usage of BMR

An important factor in being aware of your BMR is the fact that your body requires a lot of calories each day to just function, even in a state of rest.

The exact number then helps us design better meal and exercise plans for people who are trying to gain or lose weight.

For example, the average male consumes about 2,500 calories per day, while the average BMR of a male is around 1,700 calories. This means, that 1,700 calories out of 2,500, or roughly 70% of our daily calorie intake, is needed to just maintain our biological functions. All the extra calories are used on actual activities like walking, sports, talking, or other physical activities.

For people trying to reach a calorie deficit, it is important to know how many more calories a day they need to burn by doing sports, aside from the BMR calories.

For people trying to reach a calorie surplus, it is important to know how many calories will be burned just by the BMR, in order to know how many more calories they need to intake to reach their goals.

The value of BMR is affected by various aspects, such as gender, age, height, weight, lean body mass, and potential diagnosis.

Types of BMR

The concept of BMR has been researched and revisited by the scientific community many times over the last century.

Most of the BMR formulae yield very similar results but offer various tweaks and considerations.

Here are the 4 most commonly used BMR formulae as of today, all of which are available to use with our calculator. Note, that all of these formulae require you to input the weight in kilograms and the height in centimeters. The age is always in years.

Mifflin-St Jeor

One of the most commonly used equations, considered accurate for most people.

Male: BMR = 10×WEIGHT+6.25×HEIGHT−5×AGE+5

Female: BMR= 10×WEIGHT+6.25×HEIGHT−5×AGE−161

Harris-Benedict

An older equation that has been widely used but may not be as accurate for all individuals.

Male: BMR = 66.5+(13.75×WEIGHT)+(5.003×HEIGHT)−(6.75×AGE)

Female: BMR = 655.1+(9.563×WEIGHT)+(1.850×HEIGHT)−(4.676×YEARS)

Harris-Benedict Revised

A revised version of the original Harris-Benedict equation, updated for modern use.

Male: BMR = 88.362+(13.397×WEIGHT)+(4.799×HEIGHT)−(5.677×AGE)

Female: BMR = 447.593+(9.247×WEIGHT)+(3.098×HEIGHT )−(4.33×AGE)

Katch-McArdle

This equation requires knowledge of your body fat percentage and is typically used by those with more detailed body composition information. This formula also does not require gender differentiation. Your lean body mass is the remainder of your body mass, after subtracting the body fat part.

BMR = 370+(21.6×LEAN BODY MASS in KG)

Sample Calculation

Kate is a 32-year-old woman, who wants to find out what her BMR is. She decided to use the Mifflin – St Jeor formula due to its widespread usage. Kate is 172 cm tall and weighs 52 kg.

We write out the formula for the BMR and input the values. We make sure we choose the FEMALE version, as Kate is a woman.

BMR= 10×WEIGHT+6.25×HEIGHT−5×AGE−161

 = (10*52)+(6.25*172)-(5*32-161) = 1274

This means that Kate needs 1274 calories per day, just to maintain her biological function.

Using the BMR Calculator

To use our calculator, you need to follow these steps: