BMR Calculator – Calculate Your Basal Metabolic Rate

Many of us on our fitness journey must have heard the term BMR Calculator. However, most of us do not know the importance of calculating BMR.

Like several other calculators, including BMI and calorie calculators, the BMR calculator also plays a vital role in improving our efforts to get fitter and maintain a healthy body weight. It is no secret that the more we know about our body’s performance, the better we can work towards improving it. The Basal Metabolic Rate is no different. 

Everyone requires a certain amount of energy to survive, even if you decide to stay in bed all day. Recall the last time you were sick. Your body still requires you to eat food to function and heal. BMR is the minimum number of calories required. BMR calculator makes it possible for you to know your calorie requirements.

With technological advancements and more research on subjects like obesity and healthy body weight, it has become clear that calories play the most significant role in healthy body weight management.

If you plan to get into shape, build muscle or boost your immunity, the BMR calculator can help you make informed decisions. You can better prep your diet and choose exercises that fulfill your purpose, whether to lose weight or bulk up on muscles.

The good news is that your metabolism can be improved. Introducing post-meal walks and eating 3-5 nutritious meals per day using a healthy plating style can treat a variety of health concerns. HealthifyPRO, will keep you informed about your health and lifestyle in general.

A lack of fibre and protein, as well as an overreliance on simple carbs and unhealthy fats, may have an impact on your metabolism. It also allows you to track your hydration, sleep quality, and activities. Simple modifications can boost metabolism, and make a difference in your everyday life.

Let us begin with understanding what exactly is BMR and how you could use it to reach the best version of your health. 

What is BMR?

BMR stands for Basal Metabolic Rate. The importance of a healthy metabolism for a healthy body weight is well known. The term basal means basic.

So, the basal metabolic rate represents your basic metabolism. Your body burns calories even when sitting or resting and also when your digestive system is inactive. Your body is burning calories to keep your organs functioning.

For example, your body burns calories to keep your heart pumping and your lungs breathing. Whether you’re sleeping, talking on the phone, working in your office, or watching TV, your body burns a certain amount of calories for these basic actions. So, these calories add up to your BMR.

Your BMR primarily depends on involuntary functions like breathing, digestion, pumping blood, and reflex actions. Therefore, it is directly proportional to the type and intensity of the physical activity you engage in daily.

Changes in the BMR such as increased physical activity or muscle mass will increase the number of calories burnt during minimal functioning. Similarly, increased body fat will have a decreased metabolic rate or a reduced number of calories burnt during rest.

Studies by the International Journal of Obesity suggest an accurate estimation of BMR to be critical for the rigorous development of obesity control and prevention strategies. Although BMR is a standard of physical well-being, it is unique for your body, typically depending on your age, height, weight, and gender.

What is a BMR Calculator?

As the name suggests, a BMR calculator estimates your basal metabolic rate or the number of calories expended. However, it demands a neutral temperature in the environment. 

In addition, you need to calculate it when the subject’s digestive system is inactive for about 12 hours. Furthermore, it is best to measure BMR in a relaxed position.

Calculating BMI can be an excellent way to decide your adequate calorie consumption. If you know your BMR, you can better determine your caloric needs for healthy weight loss.

In addition, your BMR can help determine the number of calories you should eat to meet your goals. So, if you want to lose weight, you will need to eat less than your BMR (or maintenance calories). But, at the same time, if you wish to gain weight, you will have to eat more.

Calculating BMR – Prevalent Formulas

Calculating BMR can be easy if you understand its fundamentals. However, with advanced research, people use several formulas to do so. That is because different researchers have come up with different formulas and methods to calculate BMR. 

Harris-Benedict Formula

Harris-Benedict formulated the first equation to find BMR and revised it in 1984. It is one of the most popularly used BMR formulas. Here is the formula:

For Men

BMR = 13.397W + 4.799H – 5.677A + 88.362

For Women

BMR = 9.247W + 3.098H – 4.330A + 447.593

Mifflin-St Jeor Equation

Most of the BMR calculators also rely on the Mifflin-St Jeor Equation. Here is the formula:

For Men

BMR = 10W + 6.25 H – 5A + 5 

For Women

BMR = 10W + 6.25 H – 5A – 161 

In both the formulas given above, W is body weight (kg), H is the height (cm), A is age, and F is body fat (%)

According to a study, the Mifflin-St. Joer equation is a useful method. However, there also exist questions about its variation in accuracy levels across populations.

For example, it is low in accuracy for the obese population and comparatively more accurate for the non-obese populous. As a result, various researchers have proposed alternative equations that are yet to be found credible. 

BMR for Women and Men – An Example

As seen above, there exists a difference in the individual formulas between men and women. Research suggests that women have slightly lower BMR compared to men. 

Let us calculate the BMR for each using examples:

• Gender: Female
• Age: 36
• Weight: 58 kg 
• Height: 170 cm 
• Physical activity: Light activity 1 to 3 days/week 

Basal Metabolic Rate = 1,790 calories/day

• Gender: Male
• Age: 52
• Weight: 69 kg
• Height: 164 cm
• Physical Activity: Daily exercise 

Basal Metabolic Rate = 2,263 calories/day 

Factors Affecting Your BMR

As per research, several factors work in combination to influence your BMR. These factors are:

Body size: Larger adult bodies have more metabolising tissue and a larger BMR. 

Amount of lean muscle tissue: Muscle burns kilojoules rapidly. Hence, lean muscle tissue can affect BMR.

Amount of body fat: Fat cells are ‘sluggish’ and burn far fewer kilojoules than most other tissues and organs of the body.

Crash dieting, starving, or fasting: Eating too few kilojoules encourages the body to slow the metabolism to conserve energy. As a result, BMR can drop by up to 15%, and if lean muscle tissue is also lost, this further reduces BMR.

Age: Metabolism slows with age due to loss of muscle tissue and hormonal and neurological changes.

Growth: Infants and children have higher energy demands per unit of body weight due to the energy demands of growth and the extra energy that the body requires to maintain its temperature.

Gender: Generally, men have faster metabolisms because they tend to be larger.

Genetic predisposition: Your genes may partly decide your metabolic rate.

Hormonal and nervous controls: The nervous and hormonal systems control your BMR. Hormonal imbalances can influence how quickly or slowly the body burns kilojoules.

Environmental temperature: If the temperature is very low or very high, the body has to work harder to maintain its average body temperature, which increases the BMR.

Infection or illness: BMR increases because the body has to work harder to build new tissues and create an immune response.

Amount of physical activity: Hard-working muscles need plenty of energy to burn. Regular exercise increases muscle mass and teaches the body to burn kilojoules faster, even when at rest.

Drugs: Drugs like caffeine or Nicotine can increase the BMR.

Dietary deficiencies: For example, a diet low in iodine reduces thyroid function and slows metabolism.

Since so many factors affect your BMR, it can be challenging to conclude whether you have a healthy BMR or not. However, any BMR is healthy if it is balanced. 

Benefits of Using a BMR Calculator

Understanding how many calories your organs will need to function efficiently helps when you are engaged in reaching your fitness goals. Hence, the importance of calculating your BMR is essential. In addition, it can help combat various health issues. Some of the critical benefits of calculating your BMI are:

Weight Management

Knowing your BMR will help you understand how many calories your body requires for optimal functioning. It will prevent you from consuming too many or too few calories.

The importance of eating balanced calories in body weight management is no secret. Since the BMR calculator gives you an exact estimation of your caloric requirements, you can plan your calorie intake as per your fitness goals.

Easy Meal Planning 

Most people try to attain quick results from rigid diet plans. These diet plans would specify the units of energy in each food. This whole process takes away the simple pleasure of enjoying food.

By using a BMR calculator, you now know your BMR, around which you can plan meals, snacks, cuisines, and whatnot. You can do away with strict calorie counting that might not be sustainable for everybody. 

Gain Muscle Strength

Healthy weight management is not only about losing weight. It also involves efforts to gain muscle strength. Gaining more muscle and more power requires greater physical training that demands more energy from your food’s nutrition.

The knowledge of your BMR will guide you with a specific combination of calorie intake based on your intensive physical training. Here you can strengthen your goals with assistance from a dietician or a gym trainer.

Manage Chronic Conditions

Managing chronic conditions like PCOS and endometriosis requires caloric restrictions and physical activity. BMR  helps meet the body’s energy requirement in such diseases without making you gain excess weight. 

A research paper suggests performing aerobics and strength activity (moderate exercise) for 30-60 minutes per day. With the help of BMR, you can quickly assess your body’s calorific needs and match it with a calorie intake spread throughout the day to result in a permanent energy balance of +/- 300 calories.

Other Benefits

• Since your calorie intake and weight management play a crucial role in managing your heart health, calculating BMR would indirectly help improve your heart health. 
• Several lifestyle diseases are a result of unhealthy eating. When you know how many calories you need, you can seek help from a nutritionist in designing a healthy meal plan to give you enough nutrition and keep your calories in check. That will reduce the risk of lifestyle diseases.
• Research says metabolic risk factors lead to changes in the metabolic system and increase the possibility of lifestyle diseases. These diseases include increased BP, glucose levels, fat in the blood, and obesity. 
• Knowing your BMR will help you decide the best ways to reach your ideal body weight and health. That can assist you in gaining an increased level of general well-being and an improved lifestyle.

BMR Calculator for Weight Loss

Your body metabolism and calorie intake are significant elements of your weight loss journey. So, your aim should be to have a well-performing metabolism and know your calorific requirements.

Once you know your body’s natural energy output, you can utilize the numbers to help you reach your weight loss goals by adjusting your calorie consumption and indulging in physical activities.

Once you have your BMR numbers, it also becomes simple to calculate and recognise how many excess or deficient calories you consumed.

• Step 1: Track your nutritional input (what you eat/drink in a day).
• Step 2: Subtract your BMR or your energy output. 
• Step 3: Subtract your exercise activity or calories burnt 
• Result: The resulting number displays excess or deficient calories.

Here is an example to understand it better:

Aman is a 35-year-old man weighing 75 kgs, and he is 157 cm tall. He wants to get into shape and achieve his fitness goals. So, he decides on using a BMR calculator to identify his BMR. Since he can only work out 1-3 times a week, the BMR calculator gives him his calorific needs as 2147 calories/day to perform basic activities.

Here’s how Aman used his BMR to understand if he is on the right track:

• Food consumption (nutritional) throughout the day: 2,460 calories
• BMR = 2,147 calories
• 20 minutes of jogging = 200 calories burnt
• 25 minutes of weight training = 125 calories burnt
• Resulting number = 2460-2147-200-125 = (-12) calories

Since the resulting number is negative, Aman is consuming fewer calories than what he is burning. 

It is no secret that you will lose weight if you do so because weight loss results from a calorie deficit. However, it does not mean you need to starve yourself.

Instead, you can plan your diet and exercise based on your BMR. You do not have to follow strict diets but be mindful of consumption based on your BMR and activity. 

Link Between Activity Levels, Weight Loss, and BMR

Along with the diet you consume, your physical activity throughout the day is vital in your BMR reading because your daily calorie needs are directly based on your activity level. 

Exercise may vary in type, intensity, and frequency throughout the week. So, there is no limitation to the type or means of exercise you choose. It can vary from jogging, swimming, dancing, yoga, Zumba, playing basketball, and daily chores like washing clothes, etc. 

Classifying Exercises/Activity Based on Intensity

• Moderate exercise: 15 -30 minutes of activity involving elevated heart rate
• Intense exercise: 45-120 minutes of activity involving elevated heart rate 
• Very Intense exercise: 2 hours or more of activity involving elevated heart rate 

Classifying Exercises/Activity Based on Frequency

• Sedentary: No or little exercise
• Light Exercise 1 to 3 times a week
• Moderate Exercise 4 to 5 times a week 
• Intense exercise 6-7 times a week 
• Very intense exercise daily/physical job (labour work)

Frequency of Exercise/Physical Activity to Daily Calorie Requirement Ratio

• Sedentary no or little exercise: Your calorie requirement is BMR*1.2
• Light Exercises 1 to 3 times a week: Your calorie requirement is BMR*1.375
• Moderate Exercises 4 to 5 times a week: Your calorie requirement is BMR*1.55
• Intense Exercises 3 to 4 times a week: Your calorie requirement is BMR*1.725
• Very Intense exercises daily: Your calorie requirement is BMR*1.9

Your BMR would change according to what type and intensity you engage in each day of the week. For example, if you want to lose weight, you need to burn more calories than the energy you get from food. You should do both of these things according to your BMR reading.

A recent blog by the Harvard Medical School gave a list of 30 gym activities and calories a person would burn while performing the activity for 30 minutes.

In addition, it mentioned the number of calories burnt if people of three varying weights engaged in them, precisely 57 kgs, 70 kgs, and 84 kgs. These may seem restrictive but may give you a slight idea about the same.

Difference Between BMR and RMR

RMR and BMR are common measurements of how much energy your body uses. Although many people use them interchangeably, they are slightly different from each other. RMR is “resting energy expenditure”, meaning the energy you burn only while resting.

However, “basal energy expenditure” is the energy you burn throughout the day via basic activities involving your body functions. A simple distinction between the two is:

• The number of calories your body burns while at rest is measured by RMR (resting metabolic rate).
• The BMR (basal metabolic rate) is the calorie needed for your body to execute its most essential processes, such as breathing, generating cells, regulating temperature, etc.

Both sound comparable, and monitoring your RMR or BMR can provide a decent benchmark for your body’s energy requirements. The main distinction is that your BMR is a more accurate calculation depending on which formula you employ.

Food’s Effect on Your BMR

Your BMR rises after you eat because you use energy to eat, digest and metabolize the food you have just eaten. The rise occurs soon after you start eating and peaks two to three hours later. Studies suggest that the BMR can change between 2-30%, depending on the meal size and the type of food you eat. 

Different foods raise BMR by differing amounts. For example: 

• Fats raise the BMR by 0–5%.
• Carbohydrates raise the BMR by 5–10%.
• Proteins increase the BMR by 20–30%.
• Hot spicy foods (for example, foods containing chilli, horseradish, and mustard) can have a significant thermic effect.

The Bottom Line

Calories are the key to achieving any fitness goal. With detailed data on food and exercises, you may know the calories you consume or burn. However, knowing how many calories you burn while at rest and performing basic activities can make a difference in deciding your calorie consumption.

Once you know the exact calorie requirement to let your body function normally, it can be easy to execute and plan your fitness efforts more accurately. That explains the importance of calculating your Basal Metabolic Rate (BMR). 

Since your BMR can vary for different individuals, it is essential to calculate it in the right environment and use the right formula. However, it can be challenging at times. So, it is best to use the most accurate BMR calculator designed by experts under the supervision of nutritionists and dieticians.

So, use the most accurate BMR calculator by HealthifyMe that will help you decode the specific needs of your body to help you reach your desired goals.

Frequently Asked Questions (FAQs)

Q. What is a good BMR?

A. There is no standard BMR that is considered good. Any BMR can be healthy if it is balanced. However, since several factors affect BMR, there are no standards to define a standardized healthy BMR.

Q. How can I calculate my BMR?

A. There are mainly three formulas available to calculate BMR. So, you can use the Mifflin-St Jeor Equation, the revised Harris-Benedict Formula or the Katch-McArdle Formula. However, the easiest way would be to use the digital BMR calculators available. For example, you can use an accurate BMR calculator by HealthifyMe here. 

Q. How much BMR is normal?

A. Since BMR depends on various factors, there is no normal range for BMR. However, any BMR is healthy if you balance it well. It indicates how many calories you burn while at rest and helps you decide how many calories you should consume to maintain healthy body weight.

Q. What is a good BMR for my age?

A. BMR is usually calculated for adults between 18 and 80. All factors, including age, sex, exercise, diet, height, weight, etc., play an essential role in determining if your BMR is suitable for your age. If you balance it, any BMR is healthy.

Q. What is the ideal BMR for a woman?

A. There exist variations depending on various other factors, including age, physical activity, height, weight, pregnancy status, muscle mass, etc. For example, a woman who is 36 years old, weighing 58 kg, with a height of 170 cm, not currently pregnant, and engages in light exercise for 1-3 days a week should approximately use 36.5 calories/hour.

Q. Should you eat below your BMR?

A. A healthy individual should not eat below their BMR as it could result in unhealthy weight loss, loss of muscle mass, and deficiency of vitamins and minerals, eventually leading to problems in proper functioning. However, if you wish to lose weight, you can eat less than your BMR under the guidance of an expert nutritionist or healthcare expert.

Q. How many calories should I eat based on my BMR?

A. The number of calories you should consume depends on your fitness goals. If you are eating fewer calories than your BMR, it can hamper your body’s regular functioning. However, if you eat more calories than your BMR, you can burn them through exercise and physical activity to achieve healthy weight loss goals. So, to simplify it, you should eat more calories to gain weight. Whereas, if you want to lose weight, you should eat fewer calories.

Q. What happens if I eat less than my BMR?

A. Since BMR is the number of calories you require for the optimum functioning of your body’s vital organs, eating less than your BMR is not advisable. It can hamper your body’s regular activities like heart functioning, respiratory system, etc. It can also lead to unhealthy weight loss, loss of muscle mass, and deficiency of vitamins and minerals, eventually leading to problems in healthy body functioning. However, if you aim to lose weight, you can eat fewer calories. But, you should always do so under the guidance of an expert.

Q. What foods speed up your metabolism?

A. Foods that might help speed up your metabolism are cottage cheese, lentils, apple cider vinegar, whole grains, chillies, chia and flax seeds, coconut oil, and yoghurt.

Q. What drinks help boost metabolism?

A. Green tea, chilli guava lemonade, a spinach kale smoothie, apple cinnamon water, protein shakes, coconut water, apple cider shots, and ginger shots are a few drinks that can help boost your metabolism. 

Q. Is 1500 calories a day enough?

A. The number of calories your body needs depends on your BMR readings. Your BMR will help you know how many calories you need for the vital organs of your body to function. However, It will differ for different individuals. Hence, it is essential to calculate your BMR and identify the adequate calories that you require.

Q. Why is BMR important?

A. BMR is the amount of energy your body uses when you are at rest and the calories you burn while performing regular functions of your body organs. As a result, it helps you assess the number of calories you require to function normally. Hence, BMR acts as a guide to efficiently plan and achieve one’s fitness goals. In addition, it can help you plan meals, choose exercises, and engage in activities that help you lead a healthy life for a long time. 

Q. Should BMR be high or low?

A. A high or low BMR depends on various factors like age, sex, exercise, diet, etc. For example, a teenager in his puberty may have a high BMR during the time of a rapid growth spurt. At the same time, an older adult of 75 years of age may require a lower BMR/calories/day to function. 

Q. How does stress affect BMR?

A. Cortisol, the stress hormone, can be a leading cause of obesity in many individuals. In healthy individuals, stress can increase the rate at which your heart pumps blood, affecting your metabolic performance. In addition, stress directly or indirectly affects the quantity and quality of your diet. For example, some like to overexert themself during stressful times, while others do not want to engage in exercise. All these things together affect one’s BMR.

Q. What are the 5 major factors for a person’s metabolism?

A. Five significant factors for a person’s metabolism include their age, gender, height, weight, and the type and intensity of physical activity they engage in.

Q. How does body composition affect BMR?

A. Body composition includes the composition of fat tissues, muscle mass, water weight, body size, and surface area. All these elements contribute to the gross body weight, which helps identify whether your body metabolism is fast or slow, affecting the BMR. 

Q. How does muscle affect BMR?

A. People with more muscle mass usually have faster metabolisms. 

Q. Does running increase BMR?

A. Any form of physical activity has to be kept consistent to boost your BMR. So, if you run regularly, it can help improve your BMR.

Q. What foods decrease metabolism?

A. Foods that decrease your metabolism include white flour, red meat, omega-6 fatty acids, soda, fruit juices, energy bars, etc. 

Q. How is BMR related to weight loss? 

A. Your body metabolism and calorie intake are significant elements of your weight loss journey. So if you have a well-performing metabolism, your body will burn more calories while at rest. That will help you decide how many calories you require to function. Then, depending on your BMI results, you can modify your calorie consumption to reach a calorie-deficit plan, which can help you lose weight.

External Sources

Best-fitting prediction equations for basal metabolic rate: informing obesity interventions in diverse populations (2013)
https://www.nature.com/articles/ijo2012218

Bias and accuracy of resting metabolic rate equations in non-obese and obese adults (2013)
https://www.sciencedirect.com/science/article/abs/pii/S0261561413001003

Basal Metabolic Rate (2003)
https://www.sciencedirect.com/topics/medicine-and-dentistry/basal-metabolic-rate

Metabolism (n.d.)
https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/metabolism#metabolic-rate

Chapter 7 – Diet and exercise in the management of PCOS: Starting from the basics (2022)
https://www.sciencedirect.com/science/article/pii/B9780128230459000109

Calories burned in 30 minutes for people of three different weights. (2021)
https://www.health.harvard.edu/diet-and-weight-loss/calories-burned-in-30-minutes-for-people-of-three-different-weights

Disease and Mortality in Sub-Saharan Africa. 2nd edition. Chapter 18: Lifestyle and Related Risk Factors for Chronic Diseases (2006)
https://www.ncbi.nlm.nih.gov/books/NBK2290/