BMI Calculator Online
Calculate your Body Mass Index with metric or imperial units
How to Use BMI Calculator
- 1
Choose your unit system
Select metric (kg and cm) or imperial (pounds and feet/inches).
- 2
Enter height and weight
Fill in both fields. The result updates immediately as you type.
- 3
Review your BMI and category
Your BMI number, WHO category (Underweight, Normal, Overweight, Obese), and healthy weight range for your height are shown instantly.
What Is BMI Calculator
Enter your height and weight in metric or imperial units and instantly see your Body Mass Index, WHO weight category, and the healthy weight range for your height. All calculations run in your browser — your health data is never uploaded to any server, making this the most private way to check your BMI online.
Why Use BMI Calculator
- Supports both metric and imperial units — switch with one click, no manual conversion needed.
- Shows the healthy weight range for your exact height, giving you a concrete target rather than just a category.
- Maximum privacy — your weight and height never leave your browser, unlike most health-tracking websites.
- No account, no email, no app download — open the page and get your result in seconds.
- Clean mobile interface makes it easy to check on your phone at a doctor's office or gym.
Frequently Asked Questions
What BMI ranges does the WHO define?
Is BMI a reliable measure for athletes?
Does this tool store my weight or health data?
Is my data safe?
Learn more
BMI Calculator Use Cases
Pre-appointment health check
Quickly calculate your BMI before a doctor's visit or annual physical so you can discuss your weight category with your physician.
Insurance and application forms
Some insurance and immigration applications require a BMI value. Calculate it privately instead of using a website that tracks your health data.
Fitness goal setting
Use the healthy weight range output to set a realistic target weight based on your height before starting a diet or exercise programme.
Health education
Students in nursing, nutrition, and health science courses can use the tool to understand BMI calculations and their limitations.
Tips & Best Practices
- 💡BMI is a population-level screening tool, not a definitive health diagnosis. Always consult a healthcare professional for personalised advice.
- 💡If you are tracking BMI over time, weigh yourself at the same time of day (ideally morning, before eating) for consistent readings.
- 💡For a more complete picture of health risk, combine BMI with waist circumference — central obesity is a stronger predictor of cardiovascular risk than BMI alone.