BMR Calculator | Basal Metabolic Rate

BMR Calculator: A Guide to Basal Metabolic Rate

What is BMR?

BMR stands for basal metabolic rate, which is the amount of energy that a person uses at rest, when they are not doing any physical activity. It is the equivalent of figuring out how much gas an idle car consumes while parked. It is influenced by factors such as age, gender, height, weight, and body composition. BMR is the minimum number of calories that a person needs to live and maintain vital functions, such as breathing, pumping blood, and keeping the brain and organs working.

Why is BMR important?

Knowing your BMR can help you plan your diet and exercise routine according to your goals. If you want to lose weight, you need to create a calorie deficit, which means consuming fewer calories than your BMR. If you want to gain weight, you need to create a calorie surplus, which means consuming more calories than your BMR. If you want to maintain your weight, you need to balance your calorie intake and output, which means consuming the same amount of calories as your BMR.

However, BMR is not the only factor that determines how many calories you burn in a day. Your total daily energy expenditure (TDEE) also includes the calories burned by physical activity and digestion. TDEE can vary significantly depending on your activity level, frequency and intensity of exercise, and type and amount of food you eat. Therefore, it is important to monitor your weight and adjust your calorie intake and expenditure accordingly.

How is BMR calculated?

There are different methods to estimate BMR, but they all involve using mathematical equations that use various variables and coefficients. Some of the most common equations are:

Mifflin-St Jeor Equation

The Mifflin-St Jeor Equation, which is considered by many experts to be the most accurate equation for calculating BMR for most types of people. It uses the following formulas:

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

Revised Harris-Benedict Equation

The Revised Harris-Benedict Equation, which is a modification of the original Harris-Benedict Equation that was developed in 1919. It uses the following formulas:

For men: BMR = 13.397 × weight(kg) + 4.799 × height(cm) − 5.677 × age(years) + 88.362

For women: BMR = 9.247 × weight(kg) + 3.098 × height(cm) − 4.330 × age(years) + 447.593

Katch-McArdle Formula

The Katch-McArdle Formula, which is slightly different from the other equations in that it calculates resting daily energy expenditure (RDEE), which takes lean body mass into account. Lean body mass is the total weight of a person minus their fat mass. This equation can be more accurate for people who have a high muscle mass or a low body fat percentage. It uses the following formula:

For both men and women: RDEE = 370 + 21.6 × leanbodymass(kg)

These equations are only estimates and may have different levels of accuracy depending on the individual. For example, some people may have a higher or lower BMR than what the equations predict due to genetic factors, hormonal imbalances, medical conditions, or other factors. The only way to measure BMR accurately is through laboratory testing using specialized equipment.

How to use a BMR calculator?

A BMR calculator is an online tool that can help you estimate your BMR based on your personal information and the equation of your choice. You can use it by following these steps:

Enter your age, gender, height, and weight.
Optionally, enter your body fat percentage if you know it or have measured it.
Click on the calculate button and see your results.

The results will show you your estimated BMR in calories or kilojoules per day. You can also see your BMI (body mass index), which is a measure of your body fat based on your height and weight, and your macronutrient breakdown, which is the percentage of calories that come from protein, carbohydrates, and fat. You can use these information to design your diet and exercise plan according to your goals and preferences.

Conclusion

BMR is a measure of how many calories a person uses at rest. It is calculated by using mathematical equations that use various variables and coefficients. Knowing your BMR can help you plan your diet and exercise routine according to your goals. You can use a BMR calculator online to estimate your BMR based on your personal information and the equation of your choice. However, you should remember that BMR is not the only factor that determines how many calories you burn in a day and that it can vary depending on various factors. Therefore, you should monitor your weight and adjust your calorie intake and expenditure accordingly.