BMI Calculator for South Korea
Korea runs the full WHO Asia-Pacific ladder
Under Korean Society for the Study of Obesity (KSSO)'s scale, South Korea uses a normal range of BMI 18.5 – 22.9, overweight from 23.0 and obesity from 25.0.
Asian BMI Calculator
Measure at the midpoint between your lowest rib and the top of your hip bone, on a normal breath out. Needed to assess central obesity and waist-to-height ratio.
This calculator covers 11 published standards: WHO international, the WHO 2004 Asian action points, WHO Asia-Pacific, China's WS/T 428, Hong Kong Department of Health, Singapore HPB, Japan JASSO, Korea KSSO, the Misra Indian consensus and ADA 2026. BMI is a screening tool, not a diagnosis.
South Korea BMI classification
| BMI range | Classification |
|---|---|
| < 18.5 | Underweight |
| 18.5 – < 23 | Normal weight |
| 23 – < 25 | Overweight |
| 25 – < 30 | Obesity class I |
| 30 – < 35 | Obesity class II |
| ≥ 35 | Obesity class III |
Source: KSSO — Diagnosis of Obesity: 2022 Update of Clinical Practice Guidelines (J Obes Metab Syndr 2023;32:121-129) · KOSSO — 2024 Obesity Fact Sheet (definitions of obesity and abdominal obesity) · Perspective on Diagnostic Criteria for Obesity and Abdominal Obesity in Korean Adults(2022 Clinical Practice Guidelines for Obesity — diagnosis section)
Why South Korea's cut-points look the way they do
Korea's KSSO adopted the WHO Asia-Pacific criteria in full: overweight from BMI 23.0, obesity from 25.0, with obesity split into three classes (25.0–29.9, 30.0–34.9, ≥35.0).
The 2022 guideline update kept the two headline numbers unchanged and instead shifted emphasis: the diagnosis now leans on morbidity — the presence of obesity-related disease — rather than BMI alone as the reason to treat. KSSO's stated position is that the earlier cut-points are justified because obesity-related disease risk rises linearly below BMI 25 in Korean adults.
Abdominal obesity is handled separately and has its own dedicated numbers: waist 90 cm or more in men, 85 cm or more in women. These correspond to the waist values that predict a visceral fat area of 100 cm² in Korean men and 70 cm² in Korean women.
Key points
- Overweight 23.0–24.9, obesity I from 25.0 — identical cut-points to Hong Kong, different tier labels.
- Three obesity classes, the only Asian standard here that matches the WHO class structure at 30 and 35.
- Abdominal obesity: waist ≥90 cm (men) / ≥85 cm (women) — tighter for women than the mainland Chinese standard.
How South Korea compares
| Compared with | Overweight threshold | Obesity threshold |
|---|---|---|
| WHO international (global) 25 / 30 | 2.0 points lower | 5.0 points lower |
| WHO Asia-Pacific (WPRO / IASO / IOTF) 23 / 25 | same | same |
A BMI of 25.0 is classified as Obesity class I in South Korea (Obesity class I). The same value reads differently on the WHO international scale — which is why the scale has to be named.
Waist circumference and central obesity
Abdominal obesity is defined as a waist of 90 cm or more in men and 85 cm or more in women.
Waist matters because BMI cannot see where fat sits. Two people with the same BMI can have very different visceral fat, and visceral fat is the component most strongly linked to type 2 diabetes and cardiovascular disease. The ethnicity-independent screen is waist-to-height ratio: keep your waist below half your height.
All standards side by side
| Standard | Normal range | Overweight from | Obesity from | Waist / central obesity | Source |
|---|---|---|---|---|---|
| WHO international (global)World Health Organization | 18.5 – 24.9 | 25.0 | 30.0 | — | Primary source |
| WHO Expert Consultation 2004 (Asian populations)World Health Organization expert consultation, published in The Lancet | 18.5 – 22.9 | 23.0 | 27.5 | — | Primary source |
| WHO Asia-Pacific (WPRO / IASO / IOTF)WHO Western Pacific Regional Office, International Association for the Study of Obesity, International Obesity Task Force | 18.5 – 22.9 | 23.0 | 25.0 | — | Primary source |
| ChinaNational Health Commission of the PRC — health industry standard WS/T 428 | 18.5 – 23.9 | 24.0 | 28.0 | M ≥90cm / W ≥85cm | Primary source |
| Hong Kong, ChinaDepartment of Health, Centre for Health Protection — adopting the WHO Western Pacific Regional Office classification for Asian adults | 18.5 – < 23.0 | 23.0 | 25.0 | WHtR < 0.5 | Primary source |
| SingaporeHealth Promotion Board (HPB), Ministry of Health | 18.5 – 22.9 | 23.0 | 27.5 | M ≥90cm / W ≥80cm | Primary source |
| JapanJapan Society for the Study of Obesity (JASSO) | 18.5 – 24.9 | — | 25.0 | M ≥85cm / W ≥90cm | Primary source |
| South KoreaKorean Society for the Study of Obesity (KSSO) | 18.5 – 22.9 | 23.0 | 25.0 | M ≥90cm / W ≥85cm | Primary source |
| India and South AsiaConsensus statement for Asian Indians (Misra et al., JAPI 2009); Indian Council of Medical Research | 18.0 – 22.9 | 23.0 | 25.0 | M ≥90cm / W ≥80cm | Primary source |
| UK NICE guidance — Asian, Chinese, Middle Eastern and Black African/Caribbean adultsNational Institute for Health and Care Excellence (UK), guideline NG246 | 18.5 – 22.9 | 23.0 | 27.5 | WHtR < 0.5 | Primary source |
| ADA 2026 standard for Asian populationsAmerican Diabetes Association — Standards of Care in Diabetes 2026, adult overweight and obesity | 18.5 – 22.9 | 23.0 | 27.5 | M ≥90cm / W ≥80cm | Primary source |
All 11 standards shown, each read from the issuing authority's own document (linked per row). The WHO 2004 figures of 23.0 / 27.5 are public-health action points, not a redefinition of the international categories.
Frequently asked questions
- Is Korean BMI 23 already a problem?
- It is the overweight threshold under KSSO, not a disease diagnosis. The 2022 guideline stresses that treatment decisions should be driven by obesity-related morbidity — blood pressure, glucose, lipids, fatty liver — rather than the BMI number alone.
- Why is 25 obese in Korea but only overweight elsewhere?
- Because Korea adopted the WHO Asia-Pacific criteria, which sets obesity at 25.0 — ten points below the WHO international definition. Elsewhere in the world, 25 is overweight and 30 is obese.
- Does Korea use waist circumference differently from other countries?
- The Korean thresholds (≥90 cm men, ≥85 cm women) are the same as mainland China's for abdominal obesity, and stricter than the WHO international waist figures of 94 cm and 80 cm. India sets a lower women's threshold at 80 cm.
Data sources and how we verify them
Every cut-point, band and formula on this page is taken from the issuing authority's own document, listed below. We do not use second-hand summaries, and we do not fill gaps with numbers no source states.
- World Health Organization (WHO)
International cut-points (25 / 30) and the 2004 Asian action points
- National Health Commission of the PRC
China's current adult cut-points — WS/T 428 (24 / 28) and waist criteria
- Department of Health, Hong Kong, China
Hong Kong classification (23 / 25), from the Population Health Survey 2020-22
- Health Promotion Board, Singapore
Singapore's three-band risk ladder (18.5–22.9 / 23.0–27.4 / ≥27.5)
- Japan Society for the Study of Obesity (JASSO)
Japan's classification, which has no overweight tier (obesity from 25)
- Korean Society for the Study of Obesity (KSSO)
Korea's classification and abdominal-obesity waist thresholds
- Indian Council of Medical Research / Misra consensus
South Asian cut-points, including the 18.0 lower bound
- National Institute for Health and Care Excellence (NICE), UK
Lower ethnic-specific thresholds for Asian adults in the UK (23 / 27.5)
- American Diabetes Association (ADA)
2026 standards — Asian obesity at 27.5 and central obesity overriding BMI
Cut-points are population-level statistical thresholds, not individual diagnoses. If your value sits near a category line, measure your waist as well and read it alongside body-fat percentage. Last checked: 2026-09-15.
Sources
- KSSO — Diagnosis of Obesity: 2022 Update of Clinical Practice Guidelines (J Obes Metab Syndr 2023;32:121-129)
- KOSSO — 2024 Obesity Fact Sheet (definitions of obesity and abdominal obesity)
- Perspective on Diagnostic Criteria for Obesity and Abdominal Obesity in Korean Adults
Every figure above was checked against the original document. This page is general information, not medical advice.
Other countries and regions
Health Information Disclaimer
Content on this site is for general information only and does not constitute medical advice. Consult a doctor or qualified health professional for personal health concerns. Last updated: August 9, 2026.
We do not keep your information. Height, weight, waist and age are calculated entirely in your browser — nothing is uploaded to our servers, logged or stored, and the numbers are gone as soon as you close or refresh the page. We measure anonymous traffic only, never the values you type. Full detail in our Privacy Policy.
Standard documented on this page: Korean Society for the Study of Obesity (KSSO) — 2022 Clinical Practice Guidelines for Obesity — diagnosis section. This site documents 11 published standards; figures are read from each authority's own document.