Support: BMI Calculator

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Common questions

How is BMI calculated?

Weight in kilograms divided by height in metres squared. In US units, weight in pounds × 703 ÷ height in inches squared gives the same number.

What is a healthy BMI?

For adults, 18.5 to under 25 by the CDC and WHO bands. Under 18.5 is underweight, 25 to under 30 overweight and 30 or more obesity. Source: CDC, Adult BMI Categories, and WHO, Obesity and overweight fact sheet, both read on 12 October 2026.

Why are the Indian cut-offs lower?

Studies found that Asian Indians develop diabetes and heart disease at lower BMIs than Western populations. India's 2008 consensus guidelines, issued with the Ministry of Health and Family Welfare, AIIMS and ICMR, set normal at 18 to 22.9, overweight at 23 to 24.9 and obese at 25 or more.

What is the healthy weight for my height?

The weight range that gives a BMI from 18.5 to 24.9. Type your height and the page shows it: at 5 feet 9 inches it is about 125 to 169 pounds.

Does BMI work for athletes?

Not well. Muscle weighs more than fat, so muscular people can have a high BMI while being lean. Waist size and body fat measures tell more.

Can I use it for a child?

No. Children and teenagers are judged by BMI-for-age percentiles that depend on age and sex. This calculator is for adults aged 20 and over.

Is my data stored?

No. Your height and weight are worked out in your browser and never sent or kept.

Is it free?

Yes, completely free, with no sign-up.