BMI Calculator
What Is BMI?
BMI stands for Body Mass Index. It is a simple measurement that uses a person’s height and weight to estimate whether their body weight falls within a commonly used range.
Our free BMI Calculator helps you calculate your BMI quickly by entering your height in centimeters and weight in kilograms. The result also shows a general BMI category based on the calculated value.
BMI is commonly used as a basic screening measurement for adults. However, it does not directly measure body fat and should not be considered a complete measure of health.
If you want to perform other everyday calculations, visit our Free Online Calculators page for more useful tools.
How to Calculate BMI
BMI is calculated using your weight and height.
For measurements in kilograms and meters, the formula is:
BMI = Weight (kg) ÷ Height (m)²
For example, if a person weighs 60 kg and is 1.65 meters tall:
BMI = 60 ÷ (1.65 × 1.65)
The BMI is approximately 22.0.
You can use our calculator above to perform this calculation automatically without doing the formula manually.
For more information about BMI and its use as a screening measure, you can refer to the CDC’s BMI information for adults.
BMI Categories for Adults
For adults, BMI values are commonly grouped into the following categories:
- Below 18.5: Underweight
- 18.5 to 24.9: Normal weight
- 25.0 to 29.9: Overweight
- 30.0 or higher: Obesity
These ranges are general guidelines used for adults. BMI does not account for factors such as muscle mass, body composition, age, or where body fat is distributed.
BMI Calculator Example
Suppose your height is 170 cm and your weight is 70 kg.
First, convert your height into meters:
170 cm = 1.70 m
Then calculate:
70 ÷ (1.70 × 1.70) = approximately 24.2
A BMI of approximately 24.2 falls within the commonly used normal-weight range for adults.
The calculator can perform this calculation instantly when you enter your height and weight.
Why Use a BMI Calculator?
A BMI Calculator can be useful when you want a quick estimate based on your height and weight. It can help you understand which general BMI category your result falls into.
People may use BMI calculations when tracking changes in their weight, learning about basic health measurements, or discussing their weight with a healthcare professional.
However, BMI should be viewed as a screening tool rather than a diagnosis. Two people with the same BMI can have very different body compositions.
Important Limitations of BMI
BMI has some important limitations. It does not directly measure body fat, muscle mass, or overall fitness.
For example, someone who has a high amount of muscle may have a higher BMI even though they have relatively low body fat. Similarly, BMI may not fully reflect health differences related to age, sex, ethnicity, or body-fat distribution.
For this reason, BMI should not be used alone to determine whether someone is healthy or unhealthy.
Who Should Use BMI Carefully?
The standard adult BMI categories are not suitable for everyone. Children and teenagers are assessed differently, usually using age- and sex-specific growth charts.
BMI can also be less informative for athletes, people with high muscle mass, older adults, and certain other groups.
If you have concerns about your weight or health, it is better to discuss your individual situation with a qualified healthcare professional.
Frequently Asked Questions
Is the BMI Calculator free?
Yes. Our BMI Calculator is free to use online and does not require any software installation.
What information do I need to calculate BMI?
You only need your height in centimeters and weight in kilograms to calculate BMI using this calculator.
What is considered a normal BMI for adults?
A BMI from 18.5 to 24.9 is commonly classified as normal weight for adults. These ranges are general screening guidelines and do not provide a complete assessment of health.
Can BMI tell me my body fat percentage?
No. BMI uses height and weight and does not directly measure body fat percentage.
Is BMI the same for children and adults?
No. Children and teenagers are generally assessed using different BMI methods that take age and sex into account.
Should I use BMI as a medical diagnosis?
No. BMI is a screening measurement and should not be treated as a medical diagnosis. If you have health concerns, consult a qualified healthcare professional.
Explore More Free Online Calculators
If you want to perform other everyday calculations, visit our Free Online Calculators page for more useful tools.