About BMI Calculator
The BMI Calculator computes your Body Mass Index from height and weight, in metric (kg/cm) or imperial (lb/ft-in) units, and shows where you fall on the standard World Health Organization range: underweight, healthy weight, overweight or obese.
BMI is a quick screening measure of weight relative to height — it doesn't measure body fat directly, and athletes with high muscle mass can score 'overweight' while being perfectly healthy. Use it as a starting point and discuss results with a healthcare professional.
Your measurements are processed locally in your browser and never stored or transmitted.
How to Use the BMI Calculator
- Choose metric or imperial units.
- Enter your height and weight.
- Read your BMI and the category it falls into on the WHO scale.
Features
- Metric and imperial unit support
- Instant BMI with WHO category ranges
- Clear healthy-range guidance
- Private — measurements never leave your device
Frequently Asked Questions
What is a healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is considered the healthy range by the WHO. Below 18.5 is underweight; 25–29.9 is overweight; 30+ is classified as obese.
How accurate is BMI?
BMI is a screening tool, not a diagnosis. It doesn't distinguish muscle from fat, so very muscular people may score high while being healthy. Waist measurement and body-fat percentage give a fuller picture.
Is the BMI Calculator free?
Yes, the BMI Calculator is completely free with no usage limits. No signup, no account and no installation required.
Is my data safe?
Yes. All processing happens locally in your browser using JavaScript — nothing you type is uploaded or stored on our servers.