BMI Categories
BMI Calculator – Check Your Body Mass Index
Body Mass Index (BMI) is a simple measurement used to estimate whether a person’s weight falls within a healthy range for their height. A BMI Calculator makes it easy to calculate this value without performing the calculation manually. You can enter your weight and height, select your preferred measurement system, and view your BMI along with its corresponding category.
This calculator supports both metric and imperial units, making it convenient for people who measure weight in kilograms or pounds and height in centimetres, feet, or inches.
How to Use the BMI Calculator
Follow these steps to calculate your Body Mass Index.
Choose a Measurement Unit: Select Metric for kilograms and centimetres, or Imperial for pounds, feet, and inches.
Enter Your Weight: Add your current weight in the unit displayed by the calculator.
Enter Your Height: For Metric, enter your height in centimetres. For Imperial, enter your height in feet and inches.
Calculate BMI: Click the Calculate BMI button to view your result.
Check Your Category: Review your BMI value and the category displayed below it.
If you want to perform another calculation, use the Reset button to clear the previous values and return to the Metric option.
BMI Formula
BMI is calculated by dividing a person’s weight in kilograms by the square of their height in metres.
BMI = Weight (kg) ÷ Height (m)²
For example, if someone weighs 70 kg and is 1.75 metres tall, the calculation is:
BMI = 70 ÷ (1.75 × 1.75) = 22.9
The calculator converts imperial measurements into metric units before applying the same formula.
Understanding BMI Categories
For adults, the calculator uses the following BMI categories.
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Normal weight |
| 25.0–29.9 | Overweight |
| 30.0 or higher | Obesity |
These ranges are general adult screening categories. A BMI result is not a diagnosis and does not directly measure body fat or overall health.
Metric and Imperial Measurement Options
The calculator provides two ways to enter your measurements.
Metric system
Weight in kilograms (kg)
Height in centimetres (cm)
Imperial system
Weight in pounds (lb)
Height in feet (ft) and inches (in)
Choose whichever system is more convenient for you. The calculator converts the measurements internally to calculate BMI.
Why BMI Is Useful
BMI is commonly used as an initial screening measurement because it is simple to calculate and makes it easier to compare weight relative to height. It can help adults identify whether their weight falls below, within, or above standard BMI ranges.
However, BMI has limitations. It does not distinguish between muscle and fat, account fully for fat distribution, or consider every factor that affects health. A muscular person, for example, may have a higher BMI without having excess body fat.
For children and teenagers, BMI must be interpreted using age- and sex-specific growth charts rather than adult categories. Pregnancy and certain medical circumstances also require a different interpretation.
Important Information About BMI Results
The BMI shown by this calculator is rounded to one decimal place. Small differences in height or weight can change the result, so enter your measurements as accurately as possible.
A BMI result should be considered alongside other factors, including age, body composition, medical history, and lifestyle. If you are concerned about your weight or health, consult a qualified healthcare professional for appropriate guidance.
Calculate Your BMI and Understand Your Result
Use the BMI Calculator to check your estimated Body Mass Index in either measurement system. Your result can provide a useful starting point for understanding weight-related health categories, but it should not replace a complete health assessment or professional medical advice.