BMI Calculator
Calculate your Body Mass Index instantly in metric or imperial units, with WHO category context and a healthy-range indicator.
How to Use BMI Calculator
Pick your unit system: Metric (kg/cm) or Imperial (lb/ft+in).
Enter your weight and height.
Click "Calculate BMI" to see your score, WHO category, and the healthy weight range for your height.
Use the reset button to calculate for another person.
About BMI Calculator
Compute your Body Mass Index in one step using the standard World Health Organization formula, in kilograms/centimeters or pounds/feet-inches. Your result is placed on the full adult BMI scale (underweight, normal, overweight, obesity classes IโIII) with a visual scale indicator, plus the specific weight range that corresponds to a healthy BMI for your exact height. Everything is calculated locally in your browser โ your height and weight are never transmitted or stored.
Frequently Asked Questions
What is a healthy BMI range?
For most adults, the World Health Organization defines 18.5โ24.9 as the healthy band. Below 18.5 is underweight; 25.0โ29.9 is overweight; 30.0 and above falls into obesity classes I (30โ34.9), II (35โ39.9), and III (40+).
Is BMI accurate for athletes, children, or elderly people?
BMI is a population-level screening ratio, not a body-composition measurement. It does not distinguish muscle from fat, so very muscular people can register as "overweight" while being healthy, and it is not validated for children or pregnant women (age/sex-specific percentiles are used instead). Treat it as one signal among several.
Is my health data sent anywhere?
No. The calculation is pure local math in your browser tab โ no network request, no storage, no logging.
Should I make health decisions based on BMI?
No tool or calculator can replace professional medical advice. BMI is a quick screening indicator; discuss your overall health, waist circumference, blood work, and lifestyle with a qualified healthcare professional.
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