Calculator
BMI Calculator — Body Mass Index
- Calculate
- Mobile Friendly
- Accessibility Tested
- Formula Verified
- SEO Optimized
- Fast Loading
- Responsive
Version 1.0.0 · Last reviewed
How it worksShow guide
Introduction
The BMI calculator estimates Body Mass Index from height and weight using the standard adult formula. It is a screening tool, not a diagnosis of body fatness or health.
Disclaimer: This tool is for informational purposes only and is not professional medical, pharmaceutical, financial, or tax advice. Always verify doses with a licensed clinician or pharmacist.
Formula
Body Mass Index is body weight in kilograms divided by the square of height in meters.
- w — Weight in kilograms (kg)
- h — Height in meters (m)
- BMI — Body Mass Index in kg/m²
Step-by-step
- Enter your height in centimeters.
- Enter your weight in kilograms.
- Convert height to meters by dividing by 100.
- Square the height in meters.
- Divide weight by height squared to get BMI.
- Match the BMI value to an adult category band.
Worked example
For a person who is 170 cm tall and weighs 65 kg: height in meters is 1.70, height squared is 2.89, and BMI is 65 ÷ 2.89 ≈ 22.5 (Normal weight).
Use cases
- Quickly estimate BMI for personal tracking
- Compare results against WHO adult BMI categories
- Understand how height and weight interact in the BMI formula
Frequently asked questions
What is a healthy BMI range for adults?
For most adults, a BMI between 18.5 and 24.9 is classified as normal weight in WHO adult categories. Values below or above that band map to underweight, overweight, or obesity ranges. Individual health needs can differ — BMI is one screening signal, not a diagnosis or medical advice.
Is BMI accurate for athletes?
BMI does not distinguish muscle from fat, so muscular people may show a higher BMI without excess body fat. Treat the number as one input alongside waist measures, fitness, and clinical context rather than a complete picture of health.
Does this calculator work for children?
No. Child and teen BMI uses age- and sex-specific percentiles from growth charts. This tool uses the adult BMI formula only (kg/m²) and is not intended for pediatric screening or diagnosis.
What units does the calculator use?
Height is entered in centimeters and weight in kilograms. The calculator converts height to meters, squares it, and divides weight by that value to produce BMI in kg/m² with the matching adult category label.
Related tools
Popular tools
Was this helpful?
Your feedback stays on this device only — it is not sent to the Bestrao team yet.