How to use it
- Enter your height in centimeters.
- Enter your weight in kilograms.
- Click the Calculate button.
- Read your BMI and the WHO category.
Your Body Mass Index (BMI) is a quick, universal measure that compares your weight to your height. By entering height in centimeters and weight in kilograms, our free calculator instantly applies the WHO formula — weight ÷ (height in meters)² — and returns both a numeric BMI and the corresponding category (Underweight, Healthy weight, Overweight, Obese). The categories follow WHO standards: Underweight < 18.5, Healthy 18.5–24.9, Overweight 25–29.9, Obese ≥ 30. Knowing your BMI helps you gauge whether you may need to adjust diet, exercise, or seek medical advice. For example, a person 170 cm tall weighing 65 kg receives a BMI of 22.5, placing them in the Healthy weight range. Because the tool converts centimeters to meters automatically, you don’t need to do any extra math. Use the result as a screening tool, not a diagnosis, and combine it with other health indicators for a fuller picture.
Pro tips
- Round height to the nearest whole centimeter for consistency.
- If you have shoes on, subtract about 2 cm for a true measurement.
- BMI is a screening tool; combine with waist‑circumference for better insight.
- Remember the formula uses meters; the calculator does the conversion automatically.
Real-life examples
- A fitness coach wants to set a baseline for a new client.
- A doctor checks a patient’s weight status during a routine visit.
- A traveler monitors health while adjusting diet on a long trip.
Case study
Maria, 32, entered 165 cm and 78 kg, got a BMI of 28.7 (Overweight). She trimmed her diet, lost 8 kg, re‑checked and saw a BMI of 24.9, moving into the Healthy weight range.