BMI Calculator
Calculate your Body Mass Index (BMI) to check if you are underweight, normal, overweight or obese.
How to Use This BMI Calculator
- 1Enter your weight in kg
- 2Enter your height in cm
- 3Click Calculate to see your BMI
- 4Check your WHO category
Formula
BMI = Weight(kg) / Height(m)² — WHO Categories: <18.5 Underweight, 18.5-24.9 Normal, 25-29.9 Overweight, 30+ Obese
Frequently Asked Questions
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About BMI Calculator
Body Mass Index, or BMI, is a widely used screening measure that estimates whether your weight falls within a healthy range relative to your height. This free BMI calculator supports both metric (kilograms and centimeters) and imperial (pounds and feet/inches) units, so anyone can check their BMI in seconds. The formula is straightforward: BMI equals your weight in kilograms divided by your height in meters squared (BMI = kg / m2). The World Health Organization classifies BMI results into four main categories: underweight (below 18.5), normal weight (18.5 to 24.9), overweight (25.0 to 29.9), and obese (30.0 and above). Obesity is further divided into Class I (30-34.9), Class II (35-39.9), and Class III (40+). A BMI in the normal range is generally associated with lower risk of heart disease, type 2 diabetes, high blood pressure, and certain cancers. However, BMI has important limitations. It does not distinguish between muscle mass and fat mass, which means athletes or people with muscular builds may register as overweight despite having low body fat. It also does not account for fat distribution; carrying excess weight around the waist poses greater health risks than carrying it in the hips and thighs. For children and teenagers aged 2 to 20, BMI is interpreted using age- and sex-specific percentile charts from the CDC rather than fixed thresholds. If your BMI falls outside the normal range, or if you have concerns about your weight regardless of your BMI score, consult a healthcare professional for a complete assessment that includes waist circumference, body fat percentage, and medical history.