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BMI Calculator

Body Mass Index (BMI) is a popular metric to help you track your health based on body fat constituency. ...Read More


Your BMI is


What is BMI?

What is BMI?

BMI is short for Body Mass Index. It is a metric that provides a rough idea about the amount of fat a person’s body constitutes and whether they are required to reduce it or not. By calculating BMI using a BMI calculator, you can determine whether you have a healthy weight or are obese, overweight or underweight.

This information can help you keep a check on your health and take necessary action towards your fitness. By consistently checking your BMI, you can keep major health issues like diabetes, cholesterol and heart conditions at bay.

Underweight – BMI less than 18.5

Normal weight – BMI between 18.5 and 24

Overweight – BMI between 25 and 29.9

Obese – BMI above 30

What Is a BMI Calculator?

What is a Body Mass Index Calculator

A BMI calculator is an online tool that calculates your body weight index and helps you determine your BMI and your health status. You can easily use this calculator to determine whether you are overweight, underweight or healthy as per your BMI.

A body weight index calculator requires you to enter certain parameters like your height, weight and age. On the basis of this information, this tool will determine your BMI and will let you know about your possible health status.  

How to Calculate BMI?

To calculate BMI using the standard formula, you can follow the steps below:

Step 1: Multiply your height by itself.

Step 2: Divide your weight with the answer above. 

Ideal BMI for Men

The BMI calculation requires the height and weight of any person and is the same for everyone above 20 years old. The standard BMI for men ranges from 18.5 to 24.9. If a person's BMI is below 18.5, he is underweight and must consider taking measures to increase his body weight.

On the other hand, if a person’s BMI is 30 or higher, as per calculation he is overweight and is prone to obesity-related health conditions. To avoid such conditions, he must take measures to reduce his weight.

Ideal BMI for Women

Similar to men, the ideal BMI for adult women also ranges from 18.5 to 24.9. If a body index calculator shows your BMI below 18.5, you are underweight. However, if the calculator shows a BMI above 25, you are overweight.

Ideal BMI for Children

Unlike adults, the body fat constituency in children changes faster with age. It is also normal for boys and girls to have more body fat during their early teen period compared to adults.

Although the formula to calculate BMI for children is the same as for adults, gender and age play a pivotal role here. This is simply because male and female height and weight change rapidly with the onset of puberty in children. Their BMI needs to be measured using the same calculator and then compared with children of the same age and gender category.

For children, if the result on the BMI calculator is between the 5th to 85th percentile on clinical growth charts, it is considered a healthy BMI. 

Risks Associated with Being Overweight

Here is a list of crucial health risks that overweight people are vulnerable to:

  • Hernia
  • Breathing problem
  • High blood pressure
  • High triglycerides
  • Type 2 diabetes
  • Stroke
  • Heart conditions
  • High LDL cholesterol level
  • Low HDL cholesterol in blood, increasing the chances of coronary artery blockages and heart attack
  • Insulin resistance
  • Complications in gallbladder
  • Gout
  • Cataract
  • Mental health issues and clinical depression
  • Urge to frequent urination or stress incontinence
  • PCOS in women leading to menstrual irregularities and lower chances of fertility
  • Osteoarthritis or breakdown of cartilage in joints leading to pain in joints
  • Sleep apnea

Risks Associated with Being Underweight

The points below list some diseases and health issues that can affect an underweight person.

  • Growth and development delays in children
  • Malnutrition
  • Anaemia
  • Vitamin deficiencies
  • Brittle bones or osteoporosis
  • Weakened immunity leads to failure of body's ability to defend against diseases
  • Disruption in the menstrual cycle in women and complexities with conception
  • Hormonal imbalances

Is BMI Reliable?

Is BMI Reliable?

A BMI calculator is a reliable tool to calculate body fat constituency in both adults and kids regardless of their gender. However, this is a tool for getting a rough idea of your health from your current weight status. It can also produce misleading results when not comparing the age and gender of the person.

You can use the BMI calculator to track your weight journey to keep potential illnesses away. You cannot use this calculator as a diagnostic tool. 

BMI Chart


A person’s Body-Mass Index, or BMI, helps them check whether they’re a healthy weight for their height. If a person weighs less or more than the recommended weight for their height, it could lead to health issues in the future. While BMI is not the only factor individuals should consider while working on their health and fitness, it is a good starting point. To understand what your BMI is, you need to know your height and weight. You can then check your BMI against the BMI chart:  


The table below displays BMI for adults above 20 years old. The result on the BMI calculator for adults is the same for both men and women.


Weight Status

Below 18.5






Above 30


BMI Formula

BMI Formula

The standard formula to calculate BMI looks like this.

BMI= Your weight / (height^2)

To understand this, let’s assume, your height is 177 cm or 1.77 m and your weight is 70 kg.

Therefore as per the formula above, your BMI will be

BMI= 70/ (1.77*1.77)= 22.36

So, according to the body weight index calculator, your BMI falls between 18.5 and 25 which means you are healthy. 

BMI for Kids

BMI for Kids

You can calculate BMI for children using the same formula as mentioned above. However, while analysing, the BMI calculator takes the child's age and gender into account. This is because the body fat constituency in girls and boys can vary and change rapidly during their teenage years.

Therefore, the BMI percentile for age and sex classifies children as underweight, overweight and healthy. A body index calculator must only be used as an initial screening factor to determine a child’s health. Medical practitioners must consider other factors for a thorough health assessment. 

BMI Table For Children and Teens, Age 2-20

The table below displays age-for-sex BMI categories and their corresponding percentile for children and teens.

BMI Percentile

Health Status

Less than 5th percentile


5th percentile to 85th percentile

Healthy weight

85th percentile to 95th percentile


Equal or more than 95th percentile



You can use the growth charts given by the Indian Academy of Pediatrics (IAP) to calculate height, weight and BMI of children of the same age and gender. 

Limitations of an Online BMI Calculator

Despite providing a brief idea about your health, you cannot rely on an online BMI calculator. Like many other measurement tools to measure body fat, a BMI calculator also has some disadvantages. Let's take a look at a few limitations of online calculators for BMI for kids and adults.

Limitations of using BMI for Adults


  • BMI Calculator is a simple tool that roughly calculates your body fat based on your height and weight. It does not take several other factors into consideration that can affect the health of a person. Thus, the BMI health status is not always accurate.
  • Women tend to have more body fat than men for similar BMI.
  • Even if you have an average weight, your BMI might categorise you as overweight. Thus, with this, a BMI calculator can spread misinformation.
Limitations of using BMI for Young Adults and Children

Young Adults and Children

Unlike adults, BMI calculators require more information than a person’s height and weight for children. To evaluate BMI status for young adults and children, the calculator needs to know details like age and sex.

Yet the tool can provide a rough result for primary assessment. Height and weight can change very quickly in children before and after they attain puberty. The effect of puberty on physical appearance can also be drastically different. Hence, you cannot rely on body mass index value alone.    

Path to Improved Health

If your BMI calculator results diagnose your health status to be overweight or obese, it's high time to take action right away. You can inculcate the following habits to adjust your BMI to healthy levels:
Exercise Regularly to improve health

Exercise Regularly

Start with short exercises focusing on cardio and weight loss to burn calories and improve your blood circulation. You can also move ahead to muscle-building exercises to lose belly fat and improve your shape. This will help strengthen your body to defend against heart issues and conditions like cholesterol. 

Eat Healthy Food to maintain great health

Eat Healthy Food

With exercise, you must also look after your diet and try to cut down your intake of oily and high-calorie-rich foods. Instead, you must focus on a more protein-rich diet by including fruits, lean meat, vegetables and whole grain items in your meal. 

Avoid Overeating

Avoid Overeating

Dieting can increase your cravings to overeat during cheat days. In such instances, you must be mindful of your portion to allow smooth digestion. This will prevent excess undigested nutrients from getting stored as fats. 

Alternate Estimates of Weight-Related Health Risks

As already discussed, BMI calculators are not always a reliable option for knowing your health status. Instead of BMI, you can use the following alternative methods to track your weight. 


Waist Circumference

Measuring your waist helps to determine fat stored in your body more accurately than BMI. With waist circumference, you can know where most fat in your body is getting stored and whether you are overweight or not.

If your waist circumference is above 35 inches for women and 40 inches for men, you might run a higher health risk of contracting chronic illnesses. To measure your waist circumference, place a tape around your mid-region, above your hip bones and measure the circumference. 


Waist-to-Hip Ratio

Waist-to-hip ratio is another way for doctors and dieticians to determine whether you are overweight, obese or underweight. To calculate your health status, this ratio takes fats stored around your hips, waist and buttocks into consideration.

Unlike BMI, waist-to-hip ratio is a comparison between the fat stored around your waist and hips. As per research, people who carry more weight around their waist-hip region tend to be overweight. They stand at high risk of health conditions like type-2 diabetes and other health issues.

The World Health Organisation states that the ideal waist-to-hip ratio for men is 0.9 or less and for women, it is 0.85 or less. 


Waist-to-Height Ratio

This ratio compares your waist circumference to your height and presents results to reflect fat distribution in your body.  According to studies, a person's weight-to-height ratio is a good indicator of their vulnerability to heart attack and other health conditions related to obesity.

The ideal weight-to-height ratio is 0.50 for both men and women. A ratio above 0.50 indicates that the person is verging towards obesity and will be vulnerable to health issues like diabetes and high cholesterol.

BMI Calculator - FAQs

1 How do I calculate my BMI?

You can calculate BMI manually by using the formula: BMI= Weight / (height^2). For instant results, you can opt for a BMI calculator available online. 

2 Is a BMI of 20 a lot?

According to the BMI chart for adults, if your body mass index is 20, you are in great shape and health. 

3 What is the ideal BMI range?

The ideal BMI range for both male and female adults is between 18.5 and 24.9. 

4 How is BMI measured?

To measure body mass index using the BMI calculator, you must enter your height, weight and age. 

5 What is the ideal BMI for a man?

The ideal BMI for a man above the age of 20 years is 18.5 to 24.9. 

6 What is the ideal BMI for a woman?

The ideal BMI for an adult woman is 18.5 to 24.9. 

7 How much should I weigh for my height and age?

Consider checking your ideal weight according to height and age in a BMI chart. To resolve any confusion regarding the same, consider consulting a medical expert. 

This interactive does not constitute an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. HDFC Life Insurance Company Limited or any of its affiliates/ group companies shall not be in any way responsible for any loss or damage that may arise to any person from any inadvertent error in the information reported by the interactive.

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