BMI and BMR: What Is The Difference?

BMI and BMR have become common terms for discussion when it comes to weight management. But when it comes to BMI and BMR, do you know what is the difference? Let's read!

BMI and BMR Explained

Many of you might wonder what is BMR and what is its relationship to BMI. There is enough scientific evidence to prove that BMI and BMR are correlates of measuring body mass and weight. Simple definitions would be that BMI stands for Body Mass Index and BMR is Basal Metabolic Rate. BMI calculators and similarly BMR calculators are popularly used by persons on a weight loss regime. Yet they are two completely different methods and here’s why: BMI suggests body mass and is a measurement of your body composition from your height and weight. Typical BMI calculators are based on statistical measurement. BMR is a biological albeit natural process which shows how much calories your body burns when at rest. BMR is that energy system which is required for our vital organs and body parts to function effectively.


BMI and BMR: How are they calculated?

Image Source:

Body composition or calculating how much fat your body has can be a popular description of BMI. The key information here is that BMI simply understands your body weight and height to standardize your build. This means BMI finds out whether you are underweight, overweight, obese or within range. There are standard variations for BMI of men and women such as the BMI calculator for men would show you a measurement by your age, height, and weight. Some tests would require specific information (if you are taking a simple one online) that can ask for your descent, your dietary intakes, and gender. 
BMR calculators function similarly- only they show you how much calories your body naturally burns on an average. To seem fit within the range of weight and number of calories burnt, you can refer to standard weight measurement charts. It is said that BMR is harder to calculate and it varies between men and women.

One of the components of BMR charts is that your age is taken into account, unlike BMI calculators that conclude results only based on your height and weight. For simple (and faster results) check with needed information using an online calculator. Additionally, you can also use reliable BMI charts related to your height and weight. Standard examples on how to read BMI charts can be locating your height and weight on the left-hand side corner on the chart then see results across down. 

#Key info: How to calculate BMR and BMI are based on Harris-Benedict equations and can also be taken online. However since the calculations are different for both men and women, see the formula below. 

BMI and BMR Formulas 

How to calculate BMI is rather simple. BMR is measured in kJ and BMI is measured by dividing mass/height that is kg/m2 as a unit of measurement. BMR formula is based on the energy units spent so ideally if say, you have to lose 1kg of fat then you need to burn 3500 calories. The body’s natural processes incur a loss of calories even at rest as mentioned earlier. So the BMR charts can tell you how much you can eat to burn calories and maintain the energy balance in your body. The logic is simple: excess eating reflects fat because the BMR has only burnt calories as per your body needs. The excess then is produced as fats in your body.
BMR calculators for men and women are different because of the presence of fat in women. Fat percentages in women are slightly higher than in men. The commonly used Harris-Benedict BMR formula is applicable to men and women differently who want to check their BMRs. 



Image Source:

(The Harris–Benedict equations revised by Mifflin and St Jeor in 1990)

BMR for Men

(10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5

BMR for Women

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

#Key info: There are no such direct relations between BMI and BMR, however, it is natural to have a higher BMR if the body has more muscle mass. For example, bodybuilders have more muscle mass which gives them a higher basal metabolic rate. 

BMI vs BMR: 5 Key Differences Between BMI and BMR

BMI and BMR are two different methods of constituting body mass and energy quotient in the form of calories. 

BMI is standardized because it is a statistical measurementBMR is characterized depending upon individual age, weight, and height. 
BMI charts can give you a basic range 
BMR bases on vital requisites of the body, for example, - breathing, heart beating, digestion etc. 
BMI for women naturally vary from men as they have more muscle fat; however, with age and lifestyle tendencies (if sedentary) body might have more fat although showing a normal BMI. BMR is different for a man or a woman because it is calculated differently for both.
BMI calculators are a limited means of measurement as it does not account for cases that are not standardized.BMR can give you a personalized measurement.
BMI does not consider age or gender and other such physiological aspects. BMR depends on physiological and natural energy mechanisms of the body and is somewhat determined by genetics. 

Image Source:

Understanding The BMI Chart

  • BMI value of 15-15 BMI would mean severely underweight for an average person.
  • BMI range from 16-18 is underweight, range from 18-25 is within normal weight limits.
  • On an upscale, BMI range between 25-29/30 is overweight, and
  • If it is over a range of 30+ it is considered as type I obesity.
  • Gradually after an increase from 30-40 units, it can range up to type II or III obesity. 

Alternatively, the BMI calculation can be done by using this BMI formula:

                  Weight (kg)
BMI =      -------------------
                Height in (m2)        


Is BMI Related To BMR?

If one has higher than normal levels of muscle mass then they can have higher metabolic rates. This can be the BMI ranges for bodybuilders or athletes. Since most of the BMR and BMI calculations depend on fat percentages in the body. If higher the fat percentage, it is indicative of lower BMRs. BMI ranges differ for men and women because muscle mass and containment of fat are different for both. A higher count in BMI is associated to a higher BMR in general aspects. 

Basal metabolic rates are fixed upon body’s natural metabolism. If you have more muscle mass because of overweight tendencies according to you BMI you can still have higher BMR if you maintain an active lifestyle. 

Image Source: medicalnewstoday

#Key info: BMI and BMR calculators differ at the inference stage also. This means BMI calculators do not infer any measurement other than the average standards. BMI would detect one as overweight if they have higher muscle mass as in the case of a bodybuilder. Higher BMI does not essentially mean overweight, similarly for people with non-average heights are also not considered. 

BMI and BMR for Men and Women

As stated earlier the BMI and BMR differences for men and women are dependent on fat percentage, age, and height. There is no such ideal BMI for men and women because the goal should be to keep healthy. To keep a normal blood pressure rate and a healthy heart a BMI of less than 20 is not ideal. BMI for children or BMI chart for men and women determine statistical characteristics that should be in check with what the body needs. Food, nutrition and a healthy lifestyle are ideal conditions for a good BMR for men and women. 
Lower counts of BMI and BMR can result in a weak immune system and causes can be indicative of malnutrition. Higher counts can determine overweight related issues such as obesity, heart problems, and even diabetes. 


Ask your question