Free tool
BMI calculator
Work out your body mass index (BMI) using the WHO international ranges or the lower ranges recommended for South Asian adults, and see a healthy weight for your height.
General information, not medical advice. If you have a health condition or concern, ask a doctor.
How BMI works
Body mass index (BMI) is your weight in kilograms divided by the square of your height in metres. It is a quick, rough way to check whether your weight may be putting your health at risk.
Why there are two sets of ranges
The World Health Organization’s international ranges are used in most countries. But research has found that people of South Asian origin tend to carry more body fat, especially around the waist, at the same BMI as people of European origin, and develop conditions such as type 2 diabetes and heart disease at lower BMIs. A WHO expert group noted this for Asian populations in 2004, and Indian experts recommended lower cut-offs in 2009. Some health services, such as the NHS in England, also advise people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background to use lower thresholds.
| BMI | International (WHO) | South Asian guideline |
|---|---|---|
| Below 18 | Underweight | Underweight |
| 18.0–18.4 | Underweight | Healthy weight |
| 18.5–22.9 | Healthy weight | Healthy weight |
| 23.0–24.9 | Healthy weight | Overweight |
| 25.0–29.9 | Overweight | Obese |
| 30 and above | Obese | Obese |
Check your waist too
Where you carry fat matters as well as how much. A large waist is linked to a higher risk of diabetes and heart disease, even at a healthy BMI. Commonly used thresholds are 94 cm for men and 80 cm for women of European origin, and 90 cm for men and 80 cm for women of South Asian origin.
What BMI can’t tell you
- It doesn’t separate fat from muscle, so very muscular people may get a high BMI.
- It isn’t suitable for children and teenagers, who need age-based charts, or for pregnant women.
- It is a screening number, not a diagnosis. Your doctor will consider other things, such as blood pressure, blood sugar and family history.
Sources and further reading
- World Health Organization: Obesity and overweight
- WHO Expert Consultation (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. The Lancet, 363(9403), 157–163.
- Misra, A., Chowbey, P., Makkar, B. M. et al. (2009). Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians and recommendations for physical activity, medical and surgical management. Journal of the Association of Physicians of India, 57, 163–170.
- NHS: Calculate your BMI (including ranges for different ethnic groups)
- International Diabetes Federation (2006). The IDF consensus worldwide definition of the metabolic syndrome.