BMR Calculator

Nutrition Guide

BMR Calculator

Age (10 - 100)





1,640 Calories/day

Please enter all the details correctly.

To emphasise, I would like to present the Basal Metabolic Rate (BMR) namely, which is a measure of the number of calories needed by an individual to exist: to breathe, transport blood, keep the heart pumping and support other vital functions with no physical activity. 

 Table Of Contents 

         1.1.1 Calculating BMR 


What is BMR?

Basal Metabolic Rate (BMR) is one of the most basic terms of Nutrition and Fitness. It is the amount of calories equivalent to your body’s energy requirements to perform restorative life processes without any muscle exertion. These functions entail moving oxygen and other gases into the body’s cells, pumping blood throughout the body, manufacturing red and white blood cells, metabolism of nutrients, synthesis of proteins, and transportation of ions across cell membranes. 

  In other words, BMR is the number of calories required to maintain life if a person’s activity level is nil. BMR is therefore the amount of energy required to sustain only essential body functions without interaction. 

Factors Influencing BMR

Age: Regular BMR decreases with age also with the average rate of 5-10 percent per decade. Decrease in lean. 

Muscle Mass: With ageing, BMR is affected by lean muscle mass since individuals develop a tendency of losing muscle as they grow old. 

Sex: In general, the male BMR is higher than the female BMR depending on the level of physical activity. This is because compared to women, men usually have greater levels of muscle mass, and muscles require more calorie use for sustaining even when one is inactive. 

Body Composition: People age 60 or older have a slower metabolism because they lose muscle mass as they age and muscle tissue requires more energy than fat tissue. 

Genetics: It means that there are people with different innate tendencies that make them have either a higher or a lower BMR. 

Hormonal Levels: Hormones like thyroxine (T4), secreted by the thyroid gland, play a pivotal role enhancing BMR. It also indicated that diseases like hyperthyroid or hypothyroidism lowered or raised BMR in equal measure. 

Body Size: They hypothesised that larger people are likely to have a higher BMR compared to smaller people since they need to support more body tissues.

Environmental Temperature: Cold environment can bring changes in BMR, as the body needs to expend additional energy to warm the body tissues to the normal level. 

Calculating BMR 

There are many ways that are used to calculate the basal metabolic rate. The two generic equations that are familiar to most people are Harris-Benedict Equation and Mifflin-St Jeor Equation.
Harris-Benedict Equation

It was first established by Harris-Benedict in 1918, and has been revised in 1984; thus, it is also referred to as the Harris-Benedict Equation (Revised in 1984).  There are two equations of Harris-Benedict which were established at the preliminary stage of the twentieth century but the second equation has been formulated for getting more precise results. It bases its calculations on weight, height, age, as well as the sex of the individual involved. 

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) 

Mifflin-St Jeor Equation (1990) 

It is necessary to determine the number of calories necessary to consume daily; this equation is deemed more suitable for today’s diets because it was derived relatively recently. This in turn was calculated using the BMR formula which is the basal metabolic rate.

For men

 BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5

For women

 BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) - 161

Variability and Limitations 

Thus, even though such calculations as BMR can prove very beneficial in the estimation process, it is essential to realise that they contain some imperfections as well. These are:

Measurement Errors: One shortcoming could be where the heights and weights produced are not necessarily true figures. 

Individual Differences: Difference in genetics in addition to metabolism leads to differences. 

Environmental Factors: BMR behaviour can also be influenced by stress, temperature, as well as altitude differences. 

Health Conditions: They affect metabolic rates because the body changes in various ways like through illnesses, hormonal changes etc. improving BMR increase. 

Muscle Mass: Resistance training exercises/activities can also help one build muscles thus enhancing BMR. 

Stay Active: One has to note that moderate exercise, which includes aerobic exercises, can increase the number of calories required in a body. 

Eat Protein-Rich Foods: Protein also has a higher thermic effect than fat and carbohydrate; that is, it requires a higher amount of calories, or energy, to digest it. 

Stay Hydrated: Metabolism is said to occur in water and therefore water is critical for all cellular processes that occur in the human body. 

Adequate Sleep: Sleep disturbances observed to disrupt the metabolic process and hormonal balance of one’s body. 


To know your BMR and how best to use it when designing your diet plan is very important in managing your weight as well as your health. Therefore, by identifying the BMR and considering the TDEE, then one can be in a position to understand and adjust the diet and activity level in accordance with the individual goals and/or needs that are set out in the diet plan. However, for those persons BMR is a good starting point, however due to variance in metabolism and other factors in the lives of all people, always have to consider the usage of BMR for more of a comprehensive solution to overall health and physical fitness.

Post a Comment


Post a Comment (0)