BMI Calculator (For Adults)

BMI Calculator

BMI Calculator

BMI Chart

Category BMI Range Meaning
Underweight < 18.5 Less than the body mass necessary for health.
Normal weight 18.5 – 24.9 A healthy body weight range.
Overweight 25.0 – 29.9 Excess body weight for height.
Obese Class I 30.0 – 34.9 Moderately obese.
Obese Class II 35.0 – 39.9 Severely obese.
Obese Class III >= 40.0 Very severely obese.

Welcome to the BMI Calculator

You can use this tool to find out your BMI (Body Mass Index) value and weight status based on your age. Choose the “Metric Units” tab if you use the International System of Units or the “US Units” tab to convert units into US metric units. When you click on the calculate button, you will be taken to the result page where you will see your result. You should wait for a few seconds if the result isn’t displayed already.

What Is BMI?

BMI is a way to measure how lean or fat a person is based on their height and weight. It helps to estimate how much body tissue a person has. It is a common way to check if a person has a healthy weight for their height. The BMI value is used to put a person into one of four categories: underweight, normal weight, overweight, or obese. These categories depend on where the BMI value falls. Different regions and ages may have different BMI ranges for each category. Some categories may have subcategories like very underweight or extremely obese. Having too much or too little weight can cause health problems, so BMI is a useful way to see if a person needs more tests or actions to improve their health. The table below shows the different BMI categories that the calculator uses.

BMI Table For Adults

This is the WHO’s guide for adult body weight based on BMI values. It applies to both men and women who are 20 years or older.

BMI CategoryBMI Range (kg/m2)
Severe Thinness< 16
Moderate Thinness16 – 17
Mild Thinness17 – 18.5
Normal18.5 – 25
Overweight25 – 30
Obese Class I30 – 35
Obese Class II35 – 40
Obese Class III> 40

BMI Chart

For those that love to visualize data, you can check out this chart based on data from WHO to see how different weight and height corresponds to different weight class on the BMI scale.

BMI Table For Children

CategoryPercentile Range
Underweight< 5%
Healthy weight5% – 85%
At risk of overweight85% – 95%
Overweight> 95%

BMI formula

Below are the equations used for calculating BMI in the International System of Units (SI) and the US customary system (USC) using a 5’10”, 160-pound individual as an example:

USC Units:BMI = 703 × mass (lbs)height2 (in)= 703 × 160702= 22.96 kgm2SI, Metric Units:BMI = mass (kg)height2 (m) = 72.571.782 = 22.90kgm2

Limitations of BMI

BMI Limitations BMI is a common measure of healthy body weight, but it has some drawbacks. BMI does not account for body composition, such as muscle, bone, and fat. BMI can vary depending on age, sex, ethnicity, activity level, and other factors. BMI should be used with other methods to assess a person’s health, not as the only criterion.

For adults:

BMI is not a direct measure of body fat, but a measure of excess weight. BMI can be inaccurate for people who have different body types or proportions of muscle and fat. For example, an inactive older person may have a normal BMI, but a high percentage of body fat. This is unhealthy, while a young athlete with a high BMI due to muscle mass may be healthy. According to the CDC:

Older adults usually have more body fat than younger adults with the same BMI. Women usually have more body fat than men with the same BMI. Muscular people and athletes may have high BMIs due to their large muscle mass.

For children and teens:

BMI can also be affected by factors such as height and sexual maturity in children and teens. BMI is more reliable for obese children than for overweight children, who may have more muscle or bone mass. BMI may also differ for thin children, depending on their body composition.

However, BMI is a good indicator of body fat for most people, about 90-95%. It can be used along with other measures to help determine a healthy body weight.

Disclaimer: This website is for general information only and does not provide medical advice. You should always talk to your doctor before changing your diet, exercise, or health habits. Your doctor knows your health situation best and can give you personalized recommendations. Everyone is different, and what works for one person may not work for another. Your doctor can check your medical history, current health, and any possible risks before making any decisions about your health. It is important to take care of your well-being and seek professional medical advice to make informed choices about your health and fitness journey.