BMI Calculator
Calculate your BMI instantly with WHO categories. Free online BMI calculator, metric and imperial units, no signup required.
How to Use BMI Calculator
- Enter your weight in kilograms or pounds.
- Enter your height in centimeters or feet/inches.
- Click Calculate to compute your Body Mass Index.
- View your BMI result with WHO category classification and health range.
Why Choose Krynn Tools for BMI Calculator?
- WHO Classification: Results include official World Health Organization BMI categories — underweight, normal, overweight, and obesity classes.
- Unit Flexibility: Switch between metric (kg/cm) and imperial (lb/ft-in) units instantly.
- Instant Calculation: BMI updates in real-time as you enter your measurements.
- Health Range: See your ideal weight range based on your height alongside your current BMI.
Frequently Asked Questions
Is BMI an accurate measure of health?
BMI is a useful screening tool but doesn't account for muscle mass, bone density, or body composition. Athletes may have a high BMI due to muscle, not excess fat.
What is a healthy BMI range?
According to the WHO, a BMI of 18.5-24.9 is considered normal weight. Below 18.5 is underweight, 25-29.9 is overweight, and 30+ indicates obesity.
Does this work for children?
This calculator uses adult BMI categories. Children and teens require age-and-gender-specific BMI percentiles, which this tool does not provide.
Is my data stored?
No. Your measurements are processed locally and never leave your browser. No health data is stored or transmitted.