BMI Calculator
Calculate your Body Mass Index with metric or imperial units.
Age: 30 · Gender: male
What the BMI Calculator does
Body Mass Index (BMI) is a quick screening number that relates your weight to your height. This calculator works it out for you in either metric (kilograms and centimetres) or imperial (pounds and feet/inches) units, then shows which standard category the result falls into. It is a fast way to get a rough sense of whether your weight sits in a typical range for your height.
BMI is widely used by clinicians and health services as a first-pass indicator because it needs only two easy measurements and no special equipment. It is meant as a starting point for a conversation, not a diagnosis.
How BMI is calculated and categorised
The metric formula is weight in kilograms divided by height in metres squared (kg/m²). The imperial version multiplies pounds by 703 and divides by height in inches squared, which produces the same number. The calculator handles the maths and unit conversion so you only need to enter your figures.
The World Health Organisation bands the result as follows: below 18.5 is underweight, 18.5 to 24.9 is a healthy weight, 25 to 29.9 is overweight, and 30 or above is in the obese range. These thresholds are general guides for adults and are the same ones used on most official health websites.
What BMI does not tell you
Because BMI only looks at total weight, it cannot tell muscle from fat. A very muscular athlete can score as 'overweight' while carrying little fat, and the standard bands are less reliable for older adults, pregnant women, children and some ethnic groups. Use BMI as one signal alongside measures like waist circumference, and speak to a healthcare professional before making decisions about your health.