BMI Calculator Tool

Weight: Height:

Age: Gender:

BMI Result:

Welcome to our BMI Calculator Tool, a simple and effective way to calculate your Body Mass Index (BMI), which is a crucial indicator of your overall health. BMI is widely used by healthcare professionals to assess whether you are in a healthy weight range, underweight, overweight, or obese. The BMI measurement is based on your weight in relation to your height and provides valuable insights into your health risk levels. With this tool, you can easily calculate your BMI and understand what it means for your health.

How to Use the BMI Calculator

Using the BMI Calculator Tool is simple and quick. Follow these steps to calculate your BMI:

Step 1: Enter your weight in kilograms (kg).
Step 2: Enter your height in centimeters (cm), inches, or feet. You can choose the measurement unit using the dropdown.
Step 3: Click the "Calculate BMI" button to get your results.
Step 4: Your BMI score, classification, healthy weight range, and other detailed information will be displayed below.

What is BMI?

BMI stands for Body Mass Index, a measure that helps estimate whether a person has a healthy weight for a given height. It is a simple calculation using a person's weight and height, providing a numerical value that can categorize individuals into different weight status groups. These categories include underweight, normal weight, overweight, and obesity.

Why is BMI Important?

BMI serves as an important tool in evaluating body weight in relation to height and can help healthcare professionals assess whether an individual is at risk for health issues related to weight. These include conditions like:

Heart disease
High blood pressure
Type 2 diabetes
Sleep apnea
Certain cancers

BMI is a screening tool, not a diagnostic measure. It does not directly measure body fat percentage, so individuals with a high muscle mass (like athletes) may have a higher BMI, while still being in a healthy physical condition.

BMI Table for AdultsBMI Table for Adults

The World Health Organization (WHO) provides BMI-based weight classifications for adults (age 20 or older), which are the same for both men and women:

Classification	BMI Range (kg/m²)
Severe Thinness	< 16
Moderate Thinness	16 - 17
Mild Thinness	17 - 18.5
Normal	18.5 - 25
Overweight	25 - 30
Obese Class I	30 - 35
Obese Class II	35 - 40
Obese Class III	> 40

BMI Table for Children and Teens (Age 2-20)

The Centers for Disease Control and Prevention (CDC) recommends BMI categorization for children and teens between age 2 and 20. This classification helps determine whether a child is underweight, at a healthy weight, at risk of being overweight, or already overweight. Early detection and intervention can help manage weight-related health risks, promoting healthier lifestyles for young individuals.

Category	Percentile Range
Underweight	< 5%
Healthy weight	5% - 85%
At risk of overweight	85% - 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)
BMI = 703 × 160 / 70² = 23.0

SI, Metric Units:

BMI = mass (kg) / height² (m)
BMI = 72.57 / 1.778² = 23.0

BMI Prime

BMI prime is the ratio of a person's measured BMI to the upper limit of BMI that is considered "normal," by institutions such as the WHO and the CDC. Though it may differ in some countries, such as those in Asia, this upper limit, which will be referred to as BMI_upper, is 25 kg/m².

The BMI prime formula is:

BMI prime = BMI / 25

Since BMI prime is a ratio of two BMI values, BMI prime is a dimensionless value. A person who has a BMI prime less than 0.74 is classified as underweight; from 0.74 to 1 is classified as normal; greater than 1 is classified as overweight; and greater than 1.2 is classified as obese.

Classification Based on BMI Prime

Classification	BMI	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

BMI prime allows us to make a quick assessment of how much a person's BMI differs from the upper limit of BMI that is considered normal. It also allows for comparisons between groups of people who have different upper BMI limits.

Ponderal Index

The Ponderal Index (PI) is a similar measurement to BMI but accounts for body shape, particularly in tall individuals. It is calculated by dividing weight by the cube of height. While BMI is widely used, PI can provide additional insight into a person’s body type, especially in cases of unusual height or muscle mass.

Limitations of BMI

While BMI is a useful screening tool, it has limitations. It does not measure body fat directly and may misclassify individuals with a high muscle mass as overweight or obese. Similarly, it may underestimate body fat in older adults or those with less muscle mass. Always consult a healthcare provider for a more accurate assessment of your health.

Our BMI Calculator Tool is designed to provide a quick and reliable way to assess your body weight in relation to your height. Keep in mind that BMI is just one piece of the puzzle when it comes to evaluating overall health. Always use it in conjunction with other measurements like waist circumference, body fat percentage, and consultations with healthcare professionals.