BMI for Indians: what the numbers mean and where they fall short

Body mass index (BMI) is a quick way of relating your weight to your height. It's useful for screening, but it isn't a diagnosis. Many people also don't realise that the ranges doctors in India use are lower than the international ones you'll often see online.

How BMI is calculated

BMI = weight in kg ÷ (height in metres × height in metres)

Example: a person who weighs 70 kg and is 170 cm tall: 70 ÷ (1.7 × 1.7) = 70 ÷ 2.89 = 24.2.

The ranges used in India

A 2009 consensus of Indian experts set lower cut-offs for overweight and obesity than the global ones, and these are widely used by doctors in India:

So our 70 kg, 170 cm example, at 24.2, counts as normal on a global chart but overweight under the Indian guidance. Indian and other Asian recommendations are lower because research has found that people in these populations tend to face health risks such as diabetes and heart disease at lower BMIs, often with more body fat around the abdomen.

Guidance continues to evolve, and Indian expert groups have been discussing further changes, including looking beyond BMI alone. Your doctor will know which version to apply to you.

What BMI can't tell you

• Muscle versus fat. A fit, muscular person can have a high BMI with little body fat.
• Where fat is stored. Fat around the abdomen is linked to higher risk, and someone with a "normal" BMI can still carry a lot of it.
• Age and life stage. It's less reliable for older adults, who naturally lose muscle, and it shouldn't be used in the usual way during pregnancy.
• Children. Children and teenagers are assessed using age- and sex-specific growth charts, so the adult ranges above don't apply.
• Your overall health. Blood sugar, blood pressure, cholesterol, activity and family history all matter too.

A second simple check: your waist

Because abdominal fat matters so much, waist size is a useful addition. Indian guidance has used these limits, above which risk rises:

• Men: 90 cm
• Women: 80 cm

To measure, breathe out normally and wrap a soft tape around your bare waist, roughly level with your navel, without pulling tight.

What to do with your number

Treat BMI as a prompt, not a verdict. If yours is outside the normal range, or your waist is above the limit, it's worth talking to a doctor, especially if you have a family history of diabetes or heart disease. A doctor can order the tests that give the full picture. Avoid crash diets based on one number, and see a doctor if you've lost weight without trying.

This guide is general information, not medical advice. It's based on the 2009 consensus guidelines for Asian Indians (Misra et al.) and WHO classifications. Always ask a qualified doctor about your own health. Our BMI Calculator uses the Indian cut-offs shown above.