BMI Calculator: Know Your Body Mass Index In 2024

When trying to get an idea of your current health status, several measurement options are available to choose from. Each has its distinct advantages and disadvantages. In most cases, factors such as suitability and convenience inform the majority of choices. 

Body mass index, or BMI, is a tool that uses your weight and height to estimate your current body fat. It compares the reading to different ranges to give you an indication of your health status. Some people also refer to it as a corporal mass index.

A BMI calculator offers a simple and effective tool to perform the calculations. It gives you an estimate of your BMI depending on your input information. With this, you get a quick and easy health estimation. 

Whether you’re looking to lose weight or gain muscle, the calculator gives you a good starting point. We discuss how it works, the potential drawbacks, and how to maintain a healthy weight below.

How Does This BMI Calculator Work?

The body index calculator is designed to estimate your body mass index. In simple terms, this is an estimation of the amount of body fat you’re currently carrying. When applied to well-known reference ranges, this gives you an indication of your overall health status. 

It works by using your height and weight measurements to categorize your weight status. Once you’ve inputted the relevant data, the calculator applies the data to certain formulas to give you the output. The output estimation shows whether you’re underweight, normal, overweight, or obese.  

An important point to bear in mind is that BMI cannot tell the difference between body fat and body mass. It only takes into account the factors that you input. In this case, your height, weight, age, and gender assigned at birth. 

Because of this, you may get a reading of overweight or obese but have a low amount of body fat. This is especially the case in populations such as bodybuilders. These tend to have more muscle mass than the average person, which can throw the reading off. 

Alternatively, you can use a body fat calculator for a more accurate reading. This estimates your body fat percentage while taking more factors into account. However, BMI is often sufficient for a simplified measurement of health status.

Input Data

Using the body weight index calculator requires you to provide certain physical characteristics. The accuracy of these helps to improve the accuracy of your output reading. It requires the following information: 

• Age — BMI changes depending on age.
• Gender — Males and females have different body compositions.
• Height — Feet, inches.
• Weight — Pounds or metric units, kilograms, may be used.

Output Data

Once you’ve entered your physical characteristics, the calculator puts them into the relevant formula. The provided output will then give you the following: 

• BMI — Your number estimation. 
• Weight classification — Underweight, normal, overweight, or obese. 
• Ideal BMI Range — The healthy range for your height, sex, and age. 
• BMI Prime Number — A ratio of your BMI to the upper limit of the normal range. 
• Ponderal Index Value — Metric that assesses your body composition.

How Does This Tool Work?

This biomass index calculator works by using scientific formulas that have been proven throughout research. These are designed to provide a quick and easy estimation of your body fat and therefore health status. 

The tool indicates body fatness and potential health status. It does not measure body fat directly like some other tools can. It’s designed to give you a simple estimation based on scientific principles rather than an in-depth reading. 

This is then used against weight category ranges to give a rough estimation of health. 

These are the science-backed BMI body mass index formulas used:  

BMI Formula

United States Custom, or USC, Units:

BMI = 703 × mass (lbs)/height² (in)

SI, Metric Units:

BMI = mass (kg)/height² (in)

BMI Prime

BMI prime can be defined as a dimensionless number. This means that it represents part of the equation but is not measured on a scale of units. It compares your BMI to what is defined as normal, which in this case is 25.

A BMI prime number of less than one indicates that you’re below the normal range. A BMI prime number of over one indicates that you’re overweight.

The formula and tables below indicate the calculations used and comparison ranges for the BMI calculator tool. 

BMI Prime = BMI/25

BMI Table

Here are the tables of BMI ranges for adults and children:

For Adults

Classification	BMI (kg/m2)	BMI Prime
Severe Thinness	< 16	< 0.64
Moderate Thinness	16 – 17	0.64 – 0.68
Mild Thinness	17 – 18.5	0.68 – 0.74
Normal	18.5 – 25	0.74 – 1
Overweight	25 – 30	1 – 1.2
Obese Class I	30 – 35	1.2- 1.4
Obese Class II	35 – 40	1.4 – 1.6
Obese Class III	> 40	> 1.6

For Children

Category	Percentile Range
Underweight	< 5%
Healthy weight	5% – 85%
At risk of overweigh	85% – 95%
Overweight	> 95%

BMI Chart

The body weight index chart below offers a visual representation of the suggested relationship between your height and weight. Each of the different colors is a different BMI category from underweight to obese. 

When reading the chart, use your height and weight measurements in different units. This allows you to see where you fall in the established BMI categories. The chart offers a visual version of the BMI calculator, which uses the same formulas described above. 

To use the chart, find where your height and weight intersect. The color where the lines meet represents your suggested BMI category.

Why You Can Trust Our Expert-Backed BMI Calculator

Our BMI calculator is built using science-backed foundational formulas that have been set by trusted authorities. These include well-known organizations such as the World Health Organization and the U.S. Centers For Disease Control And Prevention. 

Using these formulas, the calculator offers reliable BMI assessments with user-friendly accessibility. When used to inform better health and wellness choices, these can help to control potential health problems and diseases.

To ensure accurate estimates, the calculator tool is regularly updated to reflect the latest health research. This ensures that the guidance given is current and medically accurate regarding population-based health issues.

Whether you’re a recreational gymgoer or a qualified health professional, the BMI calculator can provide an accurate estimation. When used correctly, this can inform better practice throughout health and exercise. 

Drawbacks Of BMI

When presenting an impartial viewpoint, there are certain drawbacks that should be taken into account. These should be considered when deciding whether to use the BMI calculator for your individual health circumstances. 

What makes BMI great is that it offers a quick and easy estimation of your overall health status using well-known physical characteristics. For this reason, it’s commonly used as the first measurement of body weight status. However, this also means there are several limitations worth noting.

The first and probably the most important is that BMI can’t tell the difference between fat mass and muscle mass. Because of this, individuals with a lot more muscle mass are often put into the overweight or obese category. Examples of common populations include bodybuilders or strength and power athletes. 

The second thing is that the BMI calculator doesn’t account for body fat distribution. This means that it doesn’t account for how much visceral fat you have. This fat type poses a bigger health risk than subcutaneous fat, which is the fat just below the skin.

Visceral fat is the fat that surrounds your internal organs. This type of fat may lead to several health issues, such as diabetes, heart disease, and high blood pressure. It’s typically caused by eating more calories than you burn and not exercising enough.

Another drawback is that BMI doesn’t measure waist circumference. This is something that is highly correlated with joint pain, type 2 diabetes, and hypertension. 

Of course, you’re never going to get a perfect nutritional tool that doesn’t have flaws. However, highlighting the ones above allows you to make a proper informed choice about using the BMI calculator. 

The main purpose of it is to provide a handy estimation rather than acting as a perfect scientific tool that accounts for everything. If you want something like this, alternative laboratory methods can be used that take longer to perform. 

With these drawbacks discussed above, the BMI calculator should be used as a guide and quick indicator of health. Other measurements such as your body fat percentage and waist size can also be taken into account.

Risks Of Being Overweight

In 2022, 1 in 8 people were living with obesity. Approximately 2.5 million adults were overweight. Of these, 890 million of them were obese. 

Being overweight or obese comes with many possible health risks. These should be taken into account when deciding on suitable lifestyle choices. The main ones include but are not limited to:

• Type 2 Diabetes — This is perhaps the most well-known one linked to being overweight or obese. It occurs when the body can no longer control or produce insulin, leading to poor blood sugar regulation. This increases the risks of heart attacks and strokes.
• Cardiovascular Diseases — This refers to a group of disorders of the heart and blood vessels. Examples include high blood pressure, heart disease, and stroke. The risk of these significantly increases with excess weight.
• Reproductive Issues — This refers to a group of conditions that affect the reproductive organs of both genders. Being overweight and obese can cause hormonal imbalances that lead to fertility issues for men and women. This can also increase the risk of complications during pregnancy. 
• Gut Issues — This relates to different conditions affecting the gastrointestinal tract, such as gut dysbiosis. This is an imbalance of microbes in the digestive system. Studies have shown a strong relationship between gut dysbiosis and being overweight or obese.Without suitable treatment, this can increase inflammation and the risk of several health problems. These include type 2 diabetes, cancer, inflammatory bowel disease, and certain mood disorders. 
• Mental Health Issues — While most people tend to focus on the physical issues of being overweight, mental health conditions play a huge role. In most cases, these are often heavily linked. Excess weight can cause mental health issues such as low self-esteem, anxiety, and depression. 

Risks Of Being Underweight

Unfortunately, awareness tends to be focused more on the risks of being overweight rather than underweight. These risks should be viewed as equally important, with several ones that need to be highlighted:

• Eating Disorders — An eating disorder can be defined as abnormal eating behaviors that negatively affect mental and physical health. They can be caused by eating too much or too little. Common eating disorders to be aware of include anorexia nervosa and bulimia. 
• Malnutrition — This happens when you get too little or too much of different nutrients, resulting in health imbalances. This imbalance can negatively affect the body’s tissues and organs. If you’re not eating enough nutrient-dense foods, this can easily occur. Common symptoms include fatigue, dizziness, coordination loss, and tingling sensations in certain body parts. This should be of particular concern in older populations.
• Mental Health Issues — These refer to behavioral or mental patterns that lead to significant dysfunctions in personal functioning. Being underweight may increase the risk of this occurring. Common examples include depression, anxiety, and low self-esteem. 
• Anemia — This is a condition in which the number of red blood cells or hemoglobin content is lower than normal. Haemoglobin is a protein that transports oxygen in red blood cells. Women are at a much higher risk of developing anemia when underweight. This is especially the case when suffering from heavy menstruation or periods. Common symptoms include exhaustion, shortness of breath, and lightheadedness.
• Osteoporosis — This is a medical condition in which bones break or become brittle due to inadequate nutrition. Nutrients, muscle mass, and body fat are all needed to maintain bone density. Being underweight can decrease bone density and cause early-onset osteoporosis. 
• Weakened Immunity — The immune system is a network of cells, tissues, and organs that fight infection and disease. Being underweight can lead to weakened immune functioning, increasing the risk of illness and infection. 

How To Maintain A Healthy Weight

Maintaining a healthy weight isn’t easy at times. A well-organized approach is often needed. This is especially the case now with the increase in convenience foods and the development of technology.

• Find Your Maintenance Calories — Maintaining a healthy weight requires a sustained energy balance. This relates to the balance between the calories you take in and the ones you burn. Use a suitable calorie calculator to estimate your maintenance calories. 
• Adopt Manageable Habits — Focusing on one healthy habit at a time is much more manageable than trying to juggle multiple ones. This can lead to being overwhelmed and frustrated, which decreases motivation. Accomplish one manageable healthy habit, then move on to another one.
• Use A Sustainable Approach — While it can often feel good to progress faster, this isn’t sustainable in the long run. Find things you enjoy doing that fit your lifestyle. Implement them into your lifestyle using a slow and sensible approach. 
• Implement Healthy Behaviours — Healthy behaviors such as adding fruits and vegetables to each meal can improve health status. Other things include taking the stairs and walking to work. Healthy behaviors should be implemented into a natural daily routine.
• Use Appropriate Supplements — While the main focus should be on consuming a balanced diet, supplements can help. Adding scientifically backed ones, such as omega-3s and vitamins and minerals, can benefit health. They can help to bridge possible nutritional gaps where needed.

Conclusion

Knowing your body mass index provides a general snapshot of your current weight status. This can be used to calculate possible health risks and make informed health choices. 

Using your BMI doesn’t give the whole story. However, it can give a useful estimation of where you are at in terms of a healthy weight range.

The BMI calculator can work as a handy tool that quickly works out your BMI on demand. While it fails to take into account some contributing factors, it’s less time-consuming compared to other methods. 

Calculating your own waist circumference and body fat percentage alongside using the BMI calculator is a good idea. It helps to eliminate some of the contributing factors and provides a more accurate representation of your overall health. 

If you’re concerned with any of the health readings you have been given, ensure you visit a healthcare professional for an in-depth check-up.

Frequently Asked Questions