BMI Calculator — Check Your Body Mass Index (Korean Standard)
Jun 23, 2026
The number on your scale tells you how much you weigh — but not whether that weight is healthy for your height. That is where BMI (Body Mass Index) comes in. BMI is the world's most widely used screening indicator for weight status, and research links it to health risks such as high blood pressure, type 2 diabetes, and cardiovascular disease. This guide covers the BMI formula, the Korean obesity classification table (Korean Society for the Study of Obesity), and the known limitations of BMI so you can interpret your result with confidence.
Enter your height and weight and get your BMI and weight-status classification right away. Free, no sign-up.
Calculate my BMI →What is BMI? The formula explained
BMI (Body Mass Index) is your weight in kilograms divided by the square of your height in metres.
BMI = Weight (kg) ÷ Height (m)²
Example: 70 kg, 1.70 m → 70 ÷ (1.70 × 1.70) ≈ 24.2
The result is a dimensionless number. A higher BMI means your weight is large relative to your height. BMI does not directly measure body fat, but it correlates well with body fat percentage at the population level and is used as a cost-effective screening tool worldwide.
How to calculate BMI — 2 steps
- Enter your height and weight — Open the BMI calculator, type in your height (cm or m) and weight (kg).
- Read your result — Your BMI value and weight-status category appear instantly, based on the Korean obesity classification standard.
Korean BMI classification table (Korean Society for the Study of Obesity)
Asian populations, including Koreans, tend to have higher body-fat percentages and greater metabolic health risks at the same BMI compared with Western populations. For this reason, the Korean Society for the Study of Obesity (KSSO) uses different cut-off values from the WHO Western standard.
| Classification | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Normal | 18.5 – 22.9 |
| Overweight (pre-obese) | 23.0 – 24.9 |
| Obese class I | 25.0 – 29.9 |
| Obese class II | 30.0 – 34.9 |
| Obese class III (severe) | 35.0 and above |
Note: The WHO Western standard sets the overweight threshold at BMI 25.0 and obesity at 30.0. The Korean standard lowers overweight to 23.0 and obesity to 25.0, reflecting the higher health risks observed in Asian populations at lower BMI values.
Limitations and important caveats
BMI is a useful screening tool, but it has well-documented limitations you should keep in mind.
- Does not account for muscle mass — Athletes with high muscle mass may have a high BMI despite low body fat. Conversely, people with low muscle mass may fall in the normal BMI range while carrying excess fat.
- Does not show body fat distribution — Visceral fat (around internal organs) carries different health risks from subcutaneous fat, and BMI cannot distinguish between them.
- Does not adjust for sex or age — Women typically have more body fat than men at the same BMI; older adults often lose muscle mass while retaining fat, which BMI does not capture.
- Not a medical diagnosis — BMI is a reference indicator only. An accurate health assessment and diagnosis must be made by a qualified healthcare professional.
Pair it with the BMR calculator
Once you know your BMI, try the Basal Metabolic Rate (BMR) calculator. BMR is the minimum number of calories your body burns at rest each day. Knowing your BMR helps you set a realistic daily calorie target for weight loss, maintenance, or gain — turning a BMI snapshot into a practical action plan.
Height + weight → instant result. Korean standard. Free.
Calculate my BMI →Frequently asked questions
Q. Why does Korea use different BMI cut-offs from the WHO Western standard?
Research shows that Asian populations develop obesity-related conditions such as type 2 diabetes and cardiovascular disease at lower BMI values than Western populations. The Korean Society for the Study of Obesity therefore set the overweight threshold at BMI 23.0 and obesity at 25.0, compared with 25.0 and 30.0 in the WHO Western classification. If you live in Korea or are of Asian descent, the Korean standard gives a more accurate health picture.
Q. Does a normal BMI mean I am healthy?
Not necessarily. BMI does not measure muscle mass, body fat distribution, or visceral fat. Someone with a normal BMI could still carry too much abdominal fat or have too little muscle (sarcopenia). Regular health check-ups that include blood tests and body composition analysis give a more complete picture.
Q. Can I use this result as medical advice?
No. The BMI calculator is a general informational tool only. It is not a substitute for professional medical advice, diagnosis, or treatment. Please consult a doctor, dietitian, or other qualified healthcare provider for personalised guidance.
Q. How does the BMR calculator help alongside BMI?
BMI tells you where your current weight sits relative to healthy ranges. The BMR calculator tells you how many calories your body needs at rest. Together, they let you set a science-based daily calorie target tailored to your weight goal — whether that is losing, maintaining, or gaining weight.