BMI Calculator
Calculate your Body Mass Index (BMI) and view your health category based on WHO guidelines.
24.2
Your BMI falls within the WHO normal weight range. Maintain a balanced diet and regular physical activity.
Healthy weight range for your height
53.5 – 72.0 kg
Unit system
Calculate your exact age
See your age in years, months, days, and more →
BMI is a screening tool, not a medical diagnosis. It does not account for muscle mass, bone density, or body composition. All calculations run locally in your browser — your measurements are never sent to any server.
Body Mass Index (BMI) is one of the most widely used health screening metrics in the world. Whether you are starting a fitness journey, preparing for a medical appointment, or simply curious about where you stand, a BMI calculator gives you an instant snapshot of your weight relative to your height. Our free online BMI calculator supports both metric (kg/cm) and imperial (lbs/ft/in) units, updates results in real time as you type, and maps your score to official WHO weight categories — all without sending any data to a server.
What Is BMI?
Body Mass Index (BMI) is a simple formula that
divides your weight in kilograms by the square of your height in meters. Developed in the
19th century and adopted globally by the World Health Organization, BMI provides a quick way
to classify adults as underweight, normal weight, overweight, or obese. While it cannot
distinguish between fat and muscle, it remains a useful population-level indicator and a
practical starting point for personal health awareness. Our tool uses the standard formula: BMI = weight (kg) ÷ height (m)².
How to Use the BMI Calculator
- Choose your unit system — Select Metric (kg and cm) or Imperial (lbs and ft/in).
- Enter your weight — Type your current body weight in the selected unit.
- Enter your height — Provide your height in centimeters or feet and inches.
- Read your BMI score — Your BMI value and WHO category update instantly on the results card.
- Check the healthy range — See the recommended weight range for your height to guide your goals.
WHO BMI Categories
- Underweight: BMI below 18.5
- Normal weight: BMI 18.5 – 24.9
- Overweight: BMI 25 – 29.9
- Obese: BMI 30 and above
Key Features
- Metric & Imperial Units
Switch between kg/cm and lbs/ft/in with one click.
- Real-Time Results
BMI and category update instantly as you adjust inputs.
- WHO Classification
Clear underweight, normal, overweight, and obese labels.
- Healthy Weight Range
See the ideal weight band for your height based on BMI 18.5–24.9.
- Visual BMI Scale
Color-coded bar shows exactly where your score falls.
- 100% Private
All math runs in your browser. No data is uploaded or stored.
Limitations of BMI
BMI does not measure body fat directly and may misclassify athletes with high muscle mass as overweight. It also does not account for age, sex, ethnicity, or fat distribution. Pregnant women, elderly adults, and children require different assessment methods. Always use BMI alongside other health indicators and consult a qualified healthcare professional for personalized advice.
Frequently Asked Questions
What is a healthy BMI?
How is BMI calculated in imperial units?
703 × weight (lbs) ÷ height (in)². Our calculator handles this conversion automatically.