"Is a BMI of 25 overweight or obese?" Search it and you'll get both answers. That's because Korea uses a different obesity cutoff from the WHO international standard. Today we'll clear up how BMI is calculated, where your number falls under the Korean standard, and how to find your healthy weight range.
What Is BMI?
BMI (Body Mass Index) estimates body fatness using only your weight and height. Devised by the 19th-century Belgian statistician Adolphe Quetelet, it's still the most widely used quick screening tool worldwide, thanks to how simple it is to calculate.
BMI = Weight (kg) ÷ (Height (m) × Height (m))
For example, at 170 cm (1.70 m) and 65 kg: 65 ÷ (1.7 × 1.7) ≈ 22.5.
The Key Point — Korea's Obesity Cutoff Is Different
This is where most confusion comes from. The WHO international standard calls 30 and above obese, but Korea (Korean Society for the Study of Obesity) and the Asia-Pacific standard call 25 and above obese. It reflects research showing that people of Asian descent face higher metabolic risk at a lower BMI than Western populations.
| BMI Range | Korea (Asia-Pacific) | WHO International |
|---|---|---|
| Below 18.5 | Underweight | Underweight |
| 18.5 – 22.9 | Normal | Normal |
| 23.0 – 24.9 | Overweight (pre-obese) | Normal |
| 25.0 – 29.9 | Obesity, Class I | Overweight |
| 30.0 and above | Obesity, Class II+ | Obese |
In other words, a BMI of 24 is "normal" under the WHO standard but already "overweight" under Korea's. Korean health checkups and hospitals mostly use the Korean standard, so even if a foreign site says "normal," it's worth checking again against it.
What's My Healthy Weight?
Convert the normal range (BMI 18.5–22.9) into weight and you get your healthy weight band.
Healthy weight range = 18.5 × Height(m)² ~ 22.9 × Height(m)²
At 170 cm, that's roughly 53.5 kg ~ 66.2 kg. However far you fall outside it becomes your gain/loss target.
Why You Shouldn't Rely on BMI Alone
BMI is fast and convenient, but not the whole story.
- Ignores muscle: A muscular athlete can score a high BMI with low body fat.
- Ignores fat distribution: The same BMI is riskier with abdominal obesity — which is why waist circumference matters too.
- Age and sex differences: The same number can mean different things by age group and sex.
Use BMI as a first-pass screening tool, then broaden to body-fat percentage, waist circumference, and lifestyle for a precise assessment.
Check It Instantly with the BMI Calculator
You can do the math by hand, but a tool is handier when you want the Korean-standard classification and how far you are from a healthy weight at a glance.
- Enter height and weight to instantly see your BMI and Korean-standard classification (underweight / normal / overweight / obese)
- Automatically calculates how many kg to lose or gain to reach a healthy weight
- Compares against average BMI by age and sex so you know where you stand
👉 Open the BMI Calculator — enter your height and weight to get a Korean-standard obesity classification, the kilograms left to a healthy weight, and where you stand versus your age group.
Conclusion
If BMI confused you, it wasn't the math — it was that there are two standards. In Korea, just remember that 25 and above is obese, and normal is 18.5–22.9. Check your number and healthy weight range, then expand to more precise measures like waist circumference and body fat from there.
