Body Mass Index (BMI) Calculation & Obesity Measurement
BMI (Body Mass Index) is an index used to evaluate obesity using height and weight. It is used as a reference standard for obesity assessment by the World Health Organization (WHO) and the Korean Society for the Study of Obesity. You can check your weight status with a simple calculation.
BMI = Weight(kg) ÷ (Height(m))²
Example: Height 170cm, Weight 65kg → BMI = 65 ÷ (1.7)² = 22.5
BMI < 18.5
There may be insufficient nutritional intake or disease. Balanced diet and health management can be considered for reference.
BMI 18.5 ~ 22.9
Healthy weight range. Regular exercise and healthy eating habits can be helpful for reference.
BMI 23.0 ~ 24.9
Weight management may be considered. Exercise and diet control can be helpful for reference.
BMI 25.0 ~ 29.9
Health risks may increase. Weight loss and lifestyle improvement can be considered for reference.
BMI ≥ 30.0
Health risks may be high. Weight management can be considered.
A. BMI is just a reference indicator. Athletes with high muscle mass can be healthy even with high BMI. Conversely, you can have 'skinny fat' with high body fat percentage even if BMI is normal. For reference assessment, it's good to measure body fat percentage and waist circumference together.
A. Yes, Asians tend to have higher body fat percentage at the same BMI compared to Westerners, so the standards are different. WHO standards consider BMI 25 or higher as overweight, but Korean/Asian standards classify BMI 23 or higher as overweight.
A. Ideal weight corresponds to the BMI range of 18.5~22.9. The formula is: Minimum ideal weight = 18.5 × (height(m))², Maximum ideal weight = 22.9 × (height(m))². For example, if your height is 170cm, ideal weight is 53.5~66.2kg.
A. No, growing children and adolescents use growth curves and percentiles according to age and gender. Childhood obesity is assessed based on weight in the top 5% among 100 children of the same age and gender.
A. Pre-pregnancy BMI can be used as a reference for appropriate weight gain during pregnancy. However, during pregnancy, weight increases due to the fetus and amniotic fluid, so BMI during pregnancy is interpreted differently from general standards. Please look for relevant information regarding weight management during pregnancy.
BMI (Body Mass Index) is an index developed by Belgian mathematician Adolphe Quetelet in 1832, calculated by dividing weight (kg) by the square of height (m). Widely used by the WHO and obesity societies as a standard for obesity assessment, it is a tool for objectively understanding your weight status with a simple calculation.
Under WHO international standards, BMI 25+ is classified as overweight and 30+ as obese. However, research shows that Asians have higher body fat percentages and greater abdominal obesity risk at the same BMI levels compared to Westerners. Therefore, Asian countries including Korea apply separate standards: BMI 23+ as overweight, 25+ as obese stage 1, and 30+ as obese stage 2. This calculator applies these Asian standards.
While BMI is a convenient indicator, it has limitations in not reflecting individual muscle mass, body fat distribution, and bone density. For example, muscular athletes may be healthy despite high BMI, while someone with normal BMI may have high body fat percentage ("skinny fat"). For more accurate health assessment, it is recommended to consider BMI alongside waist circumference, body fat percentage, and visceral fat levels.