How to use
- Choose your units (ft · in · lb or cm · kg) and enter your height and weight.
- Pick a classification. WHO international cut-offs are the default; the Asia-Pacific category is always shown alongside.
- Your BMI, both categories, the healthy weight range for your height and how far you are from it appear instantly.
This calculator gives general information only. It is not medical advice and does not replace a diagnosis.
BMI formula
| Units | Formula |
|---|---|
| US customary | BMI = 703 × weight (lb) ÷ height (in)² |
| Metric | BMI = weight (kg) ÷ height (m)² |
BMI is shown to one decimal place, and the category is taken from that displayed value — the official tables are written to one decimal (24.9, 25.0), so the two always agree.
WHO and Asia-Pacific categories
| Category | WHO (TRS 894, 2000) | Asia-Pacific / Korea (KSSO 2022) |
|---|---|---|
| Underweight | below 18.5 | below 18.5 |
| Healthy / normal | 18.5 – 24.9 | 18.5 – 22.9 |
| Overweight (pre-obesity) | 25.0 – 29.9 | 23.0 – 24.9 |
| Obesity class I | 30.0 – 34.9 | 25.0 – 29.9 |
| Obesity class II | 35.0 – 39.9 | 30.0 – 34.9 |
| Obesity class III | 40.0 and above | 35.0 and above |
The CDC uses the same adult cut-offs as the WHO. The lower Asia-Pacific thresholds come from the WHO Western Pacific Region’s 2000 report and are used in Korea by the Korean Society for the Study of Obesity (KSSO), because people of Asian descent tend to carry more body fat — and develop diabetes and high blood pressure — at a lower BMI. In the UK, NICE likewise recommends lower thresholds (23 for overweight, 27.5 for obesity) for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background.
Examples
- 5 ft 9 in, 160 lb: 703 × 160 ÷ 69² = 23.6 → healthy by WHO, pre-obese by the Asia-Pacific cut-offs.
- 5 ft 9 in, 190 lb: 28.1 → overweight (WHO).
- Healthy range at 5 ft 9 in: 125.3 – 168.6 lb (BMI 18.5 – 24.9).
- Metric: 68 kg at 165 cm gives 68 ÷ 1.65² = 24.98, displayed as 25.0 — the start of the overweight range.
Limits of BMI
- BMI does not separate muscle from fat. Muscular people can score “overweight” with little body fat, and a normal BMI can hide excess abdominal fat. The body fat calculator gives a second view.
- These categories are for adults. Children and teens are assessed with BMI-for-age percentiles, and pregnancy is managed using pre-pregnancy BMI.
- A BMI result is a screening number, not a diagnosis. Talk to a doctor or other qualified professional about your weight and health.
FAQ
Is a BMI of 25 overweight?
Yes. Under WHO and CDC adult cut-offs, 25.0 – 29.9 is overweight and 30.0 or higher is obesity. Under the Asia-Pacific cut-offs, 25.0 is already obesity class I.
Why are there two sets of cut-offs?
Research summarised by the WHO found that health risks rise at a lower BMI in many Asian populations, so the Asia-Pacific scale moves the boundaries down to 23 and 25.
What is my ideal weight?
The healthy range above is the BMI-based answer. To compare the Devine, Robinson, Miller and Hamwi formulas, use the ideal weight calculator.