Standard WHO cutoffs used globally for general populations.
About the BMI Calculator
What is this?
Body Mass Index (BMI) is a widely used screening measure that relates your weight to your height. Developed in the 19th century by the Belgian statistician Adolphe Quetelet, BMI gives a single number that helps flag whether an adult falls into an underweight, healthy, overweight, or obese range. It is not a diagnostic tool — it does not measure body fat directly — but it is a quick, inexpensive way for individuals and clinicians to identify potential weight-related health risks that may warrant further assessment.
How it is calculated
BMI is calculated as weight in kilograms divided by the square of height in metres: BMI = weight(kg) ÷ height(m)². For example, a person weighing 70 kg who is 1.75 m tall has a BMI of 70 ÷ (1.75 × 1.75) = 22.9. If you only have imperial measurements, convert pounds to kilograms by multiplying by 0.4536, and convert feet and inches to metres by multiplying the total inches by 0.0254.
Reference ranges
Frequently asked questions
Is BMI accurate for athletes or muscular people?
BMI does not distinguish between muscle and fat, so very muscular individuals may register as overweight despite having low body fat. For athletes, body fat percentage or waist-to-hip ratio may be more meaningful indicators.
Does BMI apply to children and teens?
For under-18s, BMI is interpreted using age- and sex-specific percentile charts rather than the adult ranges. This calculator is designed for adults aged 18 and over.
Should I rely on BMI alone?
No single number tells the whole story. BMI is best used alongside waist circumference, body fat percentage, blood pressure, and a discussion with your healthcare provider.
BMI Calculator
Enter your weight and height to calculate your Body Mass Index. Choose metric (kg/cm) or imperial (lb/ft) units.