BMI Calculator
Calculate your Body Mass Index. Enter your weight and height to find your BMI and see which weight category you fall into.
How to calculate BMI
Body Mass Index (BMI) is a widely used screening tool that estimates body fatness based on height and weight. It was developed by Belgian statistician Adolphe Quetelet in the 1830s and remains the most common initial measure used by healthcare providers worldwide.
The formula is BMI = weight (kg) ÷ height (m)². A person weighing 70 kg at 175 cm has a BMI of 70 ÷ (1.75)² = 22.9.
The standard categories are: Under 18.5 = Underweight; 18.5–24.9 = Normal weight; 25.0–29.9 = Overweight; 30.0 and above = Obese. These thresholds are set by the World Health Organisation.
BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat mass, meaning a muscular athlete may score as overweight. It also does not account for age, sex, or ethnicity differences in body composition.
Healthcare professionals use BMI alongside waist circumference, blood pressure, cholesterol levels, and other measurements to build a complete health picture. Use this calculator as one data point — always consult a doctor for personalised health advice.