BMR Calculator - Basal Metabolic Rate Calculator (2024)

What is BMR?

BMR stands for Basal metabolic rate, which are the minimum calories we require to live. It is influenced by lean mass each person has. A normal person BMR is the calculation of calories that each organ requires to function with, while you aren’t performing any activity. The increase in mass of muscles increases BMR. It decreases with growing age and muscle mass. Total daily energy expenditure, TDEE is the total number of calories body consumes, daily, to function. The TDEE varies numerous factors, such as age, gender, and activity level. Men tend to have higher TDEE compared to women due to more muscle mass. BMR calculator for men and women is used to calculate the basal metabolic rate.

How to use the BMR Calculator?

At first, you have to enter your gender whether you’re a male or a female. Then there is an option to write age, height, and weight. Then there are five levels of activity. You have to choose one from them. The five levels of activity in the basal metabolic rate calculator are: After you have filled the information, the calculator your BMR in calories per day and the calories you require per day.

Factors that affect your BMR

It is inversely proportional to age, for example, children have more BMR compared to a twenty-year-old adult.

It is not changed during pregnancy but during the late period of pregnancy, the increase in Basal metabolic rate is due to the fetus.

Men tend to have more muscle mass, thus their Basal metabolic rate is more than women. The BMR of females, tend to decrease faster, when the age, compared to BMR of men.

The BMR is high if you have a low-fat composition in your body. One of other reason for high BMR in male’s body is the low composition of fat compared to women.

Some individuals are born with a faster BMR compared to others, for example, the Indians and Chinese have a slow BMR, while Europeans have a fast BMR. This might also be the difference in types of diets consumed by the Europeans and Indians. The people living in tropical areas have a high BMR, for example, the Singaporeans.

The temperature outside the body also affects BMR. The external cold temperature tends to increase the BMR as it increases the extra heat needed inside the body. Short exposure to heat has little impact on BMR compared to long term exposure to heat as long term exposure tends to increase the BMR.

The body surface area is calculated by the height and the weight. The BMR tends to be high if the body surface area is high. Thin and tall people tend to have high BMR, if a short person and tall person have the same weight and their BMR was calculated, the tall person would have more BMR.

If the internal temperature of the body increases up to 0.5C the metabolic rate tends to increase up to seven percent as due to high temperature, the chemical reactions occur more quickly in the body. So a person suffering from fever and a high temperature of 42C would have an increased BMR of fifty percent.

Starving yourself or a sudden decrease in calories can decrease metabolic rate up to thirty percent. Weight loss diet with low calories can cause BMR to drop up to twenty percent. The meat eaters have a twenty percent higher metabolic rate compared to vegetarians.

The BMR is increased during exercise as it builds an extra lean tissue.

The gland that regulates the Basal metabolic rate and increases metabolic reaction is thyroxin. If more thyroxin is produced BMR increases. A condition called, thyrotoxicosis, where BMR tends to double as too much thyroxin is produced. Another condition called myxedema in which metabolic rate shrinks up to forty percent compared to BMR of a normal human, as thyroxin is produced in very little quantity. In anxiety or stress, metabolic rate increases due to tense muscles and glans that release norepinephrine.

How BMR can help in weight loss?

Another alternate definition of the Basal metabolic rate makes the relation between energy and calories really visible. It states that the Basal metabolic rate is the number of calories, required by an individual to survive or by the organs to keep functioning even when the digestive system is inactive. This statement also throws light on the relation between weight loss and BMR.

Weight is lost when the total amount of calories consumed by a person are lesser than the ones that are burnt by the individual. BMR plays a very major role in weight loss which has been elaborated below.

1- Knowing the BMR – A starting point for weight loss

Basal metabolic rate and its knowledge are considered as a ‘’starting point’’ for the weight loss process.
The initial advice given by the experts to anyone who plans on losing weight is the calculation of the basal metabolic rate.

Weight is reduced and lost once a person’s total caloric intake becomes lesser than the calories that the individual is burning throughout the day. And therefore, after knowing the BMR, you are easily put into the state of knowing how to reduce the number of calories that you consume every day. And obviously, once you do it, weight loss will easily follow afterwards. Basically, it provides you with a rough idea of the number of calories you require each day to lose some weight keeping in view the number of calories your body is ‘’naturally’’ burning through the process of doing nothing but existing.

2- You burn your calories while staying at rest

Sari Greaves who is a well-known dietician describes the calories burnt at rest as ‘’Couch-potato calories’’. Which when thought of, is practically true as you are burning those calories, not because of exercising or engaging yourself in some activity, but only because your organs are performing their activities. And more interestingly, it makes up 60 percent of the calories that you have consumed per day. The left over 40% are lost through your activities.

3- An estimation of your total calorie intake if you aim at losing weight

Long ago, people did not have the concept of obesity and how it can impact a person’s health. Then came the duration, when people only lost weight for social acceptance. However, in this world where science has progressed at its best, people are now aware of how overweight/obesity can affect the quality of life. From certain kinds of cancers to different heart diseases, all are accompanied by obesity.

Therefore, the concern towards weight is increasing day by day. And if you are someone who is all about fitness, you already know how you can calculate your total calorie intake that you need to maintain to lose some pounds. This also makes the importance of BMR in the weight-world, crystal clear.

To ascertain the calories you have to keep up your present weight, multiply your BMR by an activity factor. For example, you work in an office where your job is to sit on the desk all day long, your activity factor will be around 1.2. If however, you exercise twice or thrice a week, your movement factor is 1.375. And if you increase your exercise level by instead of exercising for twice or thrice a week, you exercise 3 to 5 times per week, then your action factor increases to 1.55. In case you're associated with games and exercise six to seven days seven days, your action factor is 1.725. In case you're preparing for a long distance race or have a physically engaging activity, your action factor is 1.9.

To make it even more clear, let’s explain it with an example. Consider a male individual of 43, with a height of 5’9 and a weight of 88. His BMR will fall around 1863 (you will require a accurate BMR calculator to calculate the value. We have mentioned the one you can use at for ease) if he is lightly active. To know the total amount of calories he needs to lose weight, simply multiply the BMR with the activity factor. And you get the desired result.

4- BMR can be altered for weight loss

People have noticed and reported, that when they start with the weight loss, they lose weight real quick. After shedding some pounds in a short duration, the process slows down and so, they lose weight very slowly. This is simply because your Basal metabolic rate decreases as you lose weight, and this means that the total calories needed by a person per day also shows a decrease.

The reason why this happens may be partially due to a decrease in muscle mass. For this purpose, experts suggest going for exercises such as squats, strength training, push-ups and etc. to maintain the BMI to some extent. (Ask your gym instructor for further details) and to lose weight at the same rate.

BMR Calculator - Basal Metabolic Rate Calculator (2024)


Which BMR calculator is most accurate? ›

Of these equations, the Mifflin-St Jeor Equation is considered the most accurate equation for calculating BMR with the exception that the Katch-McArdle Formula can be more accurate for people who are leaner and know their body fat percentage.

How do you use the BMR calculator to determine your basal metabolic rate? ›

Calculate Basal Metabolic Rate
  1. Men: BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)
  2. Women: BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years)

How accurate are BMR calculations? ›

While useful, BMR calculators are not 100% accurate. Although the Mifflin-St. Jeor equation is known as one of the most accurate calculators, its result can be off by around 10% of your true BMR. Also, without including your activity level in the equation, you're not actually calculating your daily calorie needs.

How much should I eat if my BMR is 1500? ›

At a baseline, knowing your BMR provides a caloric goal your body needs to perform basic functions. For example, a BMR of 1,500 means you need to consume at least 1,500 calories to help your body work efficiently. This knowledge is important if you plan to gain, lose or remain the same weight.

Does BMR go up or down with weight loss? ›

The calories needed for maintaining basal (resting phase) metabolism are called basal metabolic rate (BMR). BMR increases with a decrease in body weight to about 0.02 kcal/min, corresponding to each 1% decrease in body weight.

What is a good BMR for my age? ›

How to Calculate your ideal BMR?
AgeMale (calories per hour)Female (calories per hour)
2 more rows
Jun 3, 2021

What is a normal basal metabolic rate for a woman? ›

An average man has a BMR of around 7,100 kJ per day, while an average woman has a BMR of around 5,900 kJ per day. Energy expenditure is continuous, but the rate varies throughout the day. The rate of energy expenditure is usually lowest in the early morning.

What is a good resting metabolic rate? ›

Men's BMR tends to be around 1600 - 1800. This means men burn 1600 – 1800 kcal during the day at complete rest. However, remember BMR is based on your own height, weight and age, so it's not advisable to go off average numbers. Most women have a BMR of around 1550 calories a day.

Can BMR calculator be used for weight loss? ›

Your BMR is calculated based on several different factors that focus on your age, gender, current weight and activity level. Although BMR is not intended for weight loss , the tool can show you information that can help you set a realistic caloric intake for yourself--whatever your goal may be.

What is the strongest predictor of BMR? ›

Fat-free mass is the best predictor of measured BMR.

Is your BMR higher if you are overweight? ›

If you have a slow metabolism or slow BMR, your body needs fewer calories to keep it going. A fast metabolism does not necessarily lead to thinness. In fact, studies show that people with overweight/obesity often have fast metabolisms. Their bodies need more energy to keep basic body functions going.

Will I lose weight if I eat less than my BMR? ›

Should you eat less than your BMR to lose weight? Since BMR represents the minimal calorie number you need for involuntary body functions, you shouldn't consume fewer calories than your BMR. To lose weight properly, you need to consider both physical activity and your BMR.

Why am I not losing weight on 1500 calories a day? ›

While you may be eating on 1,500 calories a day, if the food is primarily processed, high in sugar, or loaded with alcohol, it can have detrimental effects on your health and your weight loss journey. Foods like these may provide calories, but still lack the essential nutrients your body needs.

Is BMR 1200 too low? ›

Full stop. Research shows that the average woman aged 20 to 60 burns about 2,000 calories a day. So even if you're aiming for 1,200 as part of a weight loss regimen, you're going way too low — especially if you're active.

How do I lose weight if my BMR is 1400? ›

How Many Calories Should I Eat Daily to Lose Weight? For example, if your BMR is 1,400 (the average for American women) and you are moderately active, your AMR would be 2,170 (1,400 x 1.55). Since a pound of fat is equal to 3,500 calories, you would need to cut 500 calories per day to lose a pound per week.

What is the most accurate way to test BMR? ›

The most accurate way to calculate your BMR is to get it tested at a lab. You'll breathe into a special mask called a calorimeter that covers your mouth and/or nose. The mask uses your breath rate to measure the calories you burn. You'll need to sleep at the lab overnight to get an accurate BMR measurement.

When to use Mifflin St. Jeor vs. Harris Benedict? ›

The most widely-used equation for estimating REE is the Harris–Benedict equation (HB) [6–7]. Following the recommendations of the American Dietetic Association (ADA) [8] the Mifflin–St Jeor (MSJ) equation is more reliable, especially in obesity [9].

Is Mifflin St. Jeor accurate? ›

The Mifflin-St Jeor equation accurately predicted the BMR of 70% of obese individuals, compared with 82% in non-obese individuals.

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