BMI Calculator (Metric and Imperial)
Calculate your BMI (body mass index) with this calculator tool. By calculating your body mass index, you can get an indication of whether your weight may be affecting your health. A BMI chart is also available. BMI is commonly used by Doctors and health professionals worldwide and is calculated using your weight and height
What Is BMI?
The body mass index measurement is the calculation of your body weight in relation to your height and is commonly used as an indicator of whether you might be in a risk category for health problems caused by your weight. Using a BMI calculator such as the one on this page, you enter your weight and height measurements. Those figures are entered into the BMI formula (more on that below) to produce your current BMI reading.
You can read more about BMI in our article, What is BMI?
The BMI classifications established by the World Health Organization (WHO) are as follows:
| Body Mass Index (kg/m2) | Classification |
|---|---|
| less than 18.5: | underweight |
| 18.5 - 24.9: | normal weight |
| 25 - 29.9: | overweight |
| 30 - 34.9: | class I obese |
| 35 - 39.9: | class II obese |
| 40 upwards: | class III obese |
BMI Shortcomings
Although BMI is commonly used as a tool to indicate whether someone is a healthy weight, it is not used to definitively diagnose obesity. Indeed, people commonly choose to take several factors into consideration for this kind of diagnosis, including age, muscle-fat ratio, waist circumference, height, sex, and bone density.
It is important to remember that BMI measurements do not make a distinction between whether you are male or female, whether you have a large or small body frame, whether you have high muscle mass and the areas in which fat is distributed around your body. So, someone who has a very muscular physique (a body builder, for example) may have a high BMI without having excess fat. For this reason, BMI is not an indicator of obesity on its own.
Some alternatives methods to BMI, including the waist-hip ratio, are discussed in our article, 5 alternatives to BMI.
BMI Formula
The official formula for BMI was devised in the 1830s by Belgian mathematician Adolphe Quetelet.
Metric BMI Formula
BMI = weight (kg) / height2 (m2)
Imperial BMI Formula
BMI = ( weight (lb) / height2 (in2) ) x 703
Learn more about how to calculate your BMI using these formulae.
BMR calculator
As well as BMI, this website also contains a BMR calculator that allows you to calculate your basal metabolic rate (the number of calories you might burn in a day if you are inactive).
If you have any questions about this calculator then please contact me.
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