Body Index Calculator
Use our Body Index Calculator to estimate your BMI from your height and weight, understand your BMI category, and see an estimated healthy weight range in seconds.
Calculate Your BMI
Enter your information below. Your result is calculated instantly in your browser.
Your Result
Enter your measurements and select Calculate BMI to see your personalized result.
What Is a Body Index Calculator?
A Body Index Calculator is a simple tool designed to estimate body mass index, commonly known as BMI. BMI compares your weight with your height and produces a numerical value that can be used as a general screening measurement for adults.
Our Body Index Calculator gives you an immediate result without requiring registration. Simply select your preferred measurement system, enter your information, and calculate your BMI.
How Does the Body Index Calculator Work?
The Body Index Calculator uses the standard adult BMI calculation. Your weight is compared with the square of your height. The tool automatically handles the conversion when you choose US units.
For example, an adult who weighs 70 kg and is 1.70 meters tall has a BMI of approximately 24.2. The calculator performs this calculation automatically and then displays the corresponding BMI category.
BMI Chart for Adults
After using the Body Index Calculator, you can compare your result with the commonly used adult BMI categories below.
| BMI | Adult Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity Class I |
| 35.0 – 39.9 | Obesity Class II |
| 40.0 or higher | Obesity Class III |
BMI, Age and Sex
Our Body Index Calculator asks for age and sex to provide additional context with your result. However, these details do not change the mathematical formula used to calculate standard adult BMI.
Adult BMI is based on height and weight. Age, sex, muscle mass, body composition and other individual factors may still be relevant when interpreting what a BMI result means for a particular person.
This calculator is designed for adults age 20 and older. BMI interpretation for children and teenagers requires age- and sex-specific growth charts and should not use the adult categories shown on this page.
Understanding Your BMI Result
The number provided by the Body Index Calculator places your result within a general adult BMI category. A result below 18.5 is categorized as underweight, while 18.5 through 24.9 is generally categorized as healthy weight. Values from 25.0 through 29.9 are categorized as overweight, and values of 30.0 or higher fall within obesity categories.
These categories can be useful for population-level screening, but BMI does not directly measure body fat. Two people with the same BMI can have different amounts of muscle and body fat.
Estimated Healthy Weight Range
In addition to your BMI result, the Body Index Calculator estimates the weight range corresponding to BMI values of 18.5 through 24.9 for the height you entered.
This range is a mathematical estimate based on BMI boundaries. It should not be interpreted as a personalized target weight or medical recommendation.
Why Use This Calculator?
The Body Index Calculator is designed to make a common health calculation fast and easy. There is no account to create, and your calculation takes place directly in your browser.
You can switch between metric and US units, making the calculator convenient whether you know your measurements in kilograms and centimeters or pounds, feet and inches.
Limitations of BMI
Although the Body Index Calculator can provide a useful screening measurement, BMI has important limitations. It does not directly distinguish muscle from fat, measure body-fat percentage or describe where body fat is distributed.
Athletes and people with substantial muscle mass may have a higher BMI without having the same body composition as another person with an identical result. Pregnancy and some medical circumstances can also make standard BMI interpretation inappropriate.
Frequently Asked Questions
What does a Body Index Calculator calculate?
It calculates body mass index, or BMI, by comparing an adult's weight with height. The resulting number is then placed into a general BMI category.
What is considered a healthy BMI?
For most adults, a BMI from 18.5 through 24.9 is generally classified as the healthy-weight range. BMI is a screening measure and is not a diagnosis.
Does age change the BMI calculation?
For adults, the standard BMI formula itself does not change with age. However, individual health circumstances can affect how a result should be interpreted.
Does sex change the BMI formula?
No. Standard adult BMI uses height and weight. Sex is not part of the mathematical formula, although body composition can differ between individuals.
Can I calculate BMI using pounds and feet?
Yes. Select US Units and enter your height in feet and inches and your weight in pounds. The calculator performs the necessary conversion automatically.
Is BMI the same as body-fat percentage?
No. BMI is calculated from height and weight. It does not directly measure body-fat percentage or distinguish fat mass from muscle mass.
Can this calculator be used for children?
This tool is intended for adults age 20 and older. BMI for children and teenagers is interpreted differently using age- and sex-specific growth references.
Is the result a medical diagnosis?
No. The result is informational and should not be used as a diagnosis or as a substitute for advice from a qualified healthcare professional.