BMI Calculator (WHO & Korean Standard)

How it works

• BMI = weight ÷ height². WHO: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30+ obese.
• Korea (Korean Society for the Study of Obesity) uses Asia-Pacific cut-offs: 23–24.9 pre-obese, 25+ obese class 1, 30+ class 2, 35+ class 3. Korean health check-ups report this standard.

FAQ

What BMI is obese in Korea?

In Korea a BMI of 25 or more is obese (class 1), lower than the WHO threshold of 30.

Worked example

Example: at 170 cm and 70 kg, BMI is 70 ÷ (1.70 × 1.70) = 24.2. That is "normal" under the WHO scale (18.5–24.9) but "pre-obese" under the Korean / Asia-Pacific scale, which starts at 23. A healthy range at 170 cm is about 53.5–72.0 kg (WHO) or 53.5–66.2 kg (Korea).

Target weight: to bring BMI to 22.9 or below at 170 cm you need to weigh about 1.7 × 1.7 × 22.9 ≈ 66.2 kg or less; for the WHO limit of 24.9 it is about 72.0 kg. Korean national health screenings report BMI along with waist circumference, blood pressure and blood tests, so a single number is only one part of the picture. Weigh yourself at the same time of day, ideally in the morning, because weight can change by 1–2 kg within a day.

Common mistakes

• Korean health check-ups (건강검진) use the Asia-Pacific thresholds: 23 for pre-obese and 25 for obese.
• BMI does not separate muscle from fat, so athletes may score high.
• A waist of 90 cm or more for men, or 85 cm for women, counts as abdominal obesity in Korea even with a normal BMI.
• Children and teenagers need age- and sex-specific growth charts, not adult BMI ranges.

Explanation checked on 2026-10-30 · Spotted an outdated value? Tell us