BMI Calculator

BMI is your weight in kilograms divided by your height in metres squared. At 175 cm and 70 kg it is 70 / (1.75 x 1.75) = 22.9. In pounds and inches the same number is 703 x weight / height squared, so 154 lb at 5 ft 9 in gives 22.7. The calculator does the unit change for you, so you can mix feet and inches with kilograms, the way most people in India know their height and weight.

Most BMI calculators use only the WHO lines: normal from 18.5 to 24.9, overweight from 25 and obesity from 30. A WHO expert group found that many Asian people face a higher risk of type 2 diabetes and heart disease below BMI 25. The Indian consensus statement of 2009 (Misra and colleagues) therefore puts overweight at 23.0 to 24.9 and obesity at 25 and above for Asian Indians. That gap matters: at 175 cm, 75 kg is a BMI of 24.5, normal on the WHO scale but overweight on the Indian one. This page shows both readings side by side, so you never have to guess which one a website used.

The healthy weight range is the BMI band turned back into kilograms for your height. At 165 cm it is 50.4 to 62.3 kg on the Asian Indian scale and 50.4 to 67.8 kg on the WHO scale. If you are outside the band, the page says how far, for example above it by about 3.2 kg, which is a more useful target than a bare number. Underweight starts below 18.5 on both scales.

For children and teens one adult line does not work, because BMI changes as children grow. Choose Child (5 to 19) and the BMI is read against children of the same age and sex. The WHO 2007 growth reference for 5 to 19 years gives a z-score and percentile: overweight is above +1 SD and obesity above +2 SD. For Indian children from 5 to 18 the page also reads the revised IAP 2015 charts, which mark overweight at the line that joins an adult BMI of 23 and obesity at the adult-equivalent 27 line. A girl of 11 at 140 cm and 38 kg has a BMI of 19.4: normal on the WHO chart but just over the IAP overweight line of 19.3.

Waist size adds what BMI misses, because fat around the middle carries more risk. Add your waist to see your waist-to-height ratio. NICE advises keeping your waist under half your height: under 0.5 is healthy, 0.5 to 0.59 is increased and 0.6 or more is high. The Indian consensus also treats a waist over 90 cm in men and 80 cm in women as abdominal obesity.

Your height, weight, age and waist stay in this browser tab. Nothing you type is sent to TaskNinja, saved or logged, and there is no account. We only count anonymous events, such as the calculator being used or a PDF being downloaded, never the numbers.

BMI is a screening number, not a diagnosis. It cannot tell muscle from fat, so athletes can read high, and it is not meant for pregnancy. Older adults and people with health conditions should read it with a doctor. The categories come from WHO, the Indian consensus statement and the IAP growth charts listed below. If your BMI or waist is above the healthy range, a check of blood sugar and blood pressure with your doctor is a good next step.