Calculate your Body Mass Index (BMI) using your height and weight. Your result is compared to both the WHO's international ranges and the lower ranges used for Indian and South Asian people.
Your height in centimetres is changed to metres, then squared (multiplied by itself).
Your weight in kilograms is divided by that number.
The result is then checked against two sets of health ranges.
BMI: Weight (kg) ÷ Height (m)²
India cutoffs: Normal 18.5 – 22.9, Overweight 23 – 24.9, Obese 25+
WHO cutoffs: Normal 18.5 – 24.9, Overweight 25 – 29.9, Obese 30+
Body Mass Index is a single number that relates your weight to your height. This calculator takes your weight in kilograms and height in centimetres, computes BMI as weight divided by height in metres squared, and places the result in two sets of categories: the WHO international cut-offs and the lower cut-offs used in Indian and South Asian guidance. It also shows the weight range that counts as normal for your height under the Indian cut-offs.
Doctors, dietitians, insurers, schools and fitness apps use BMI as a quick first screen because it needs only a tape and a scale. It cannot tell you about your health on its own, but it flags when a closer look at waist size, blood sugar or blood pressure may be worthwhile. For Indian adults the Indian cut-offs are the more relevant ones, and the calculator shows both so you can see how they differ.
1. Weigh yourself in kilograms, ideally in the morning in light clothing.
2. Measure your height in centimetres without shoes, and divide by 100 to get metres.
3. Square the height: multiply the metres by themselves.
4. BMI = Weight (kg) ÷ Height (m)².
5. Compare with the Indian cut-offs: below 18.5 underweight, 18.5 to 22.9 normal, 23 to 24.9 overweight, 25 and above obese.
6. For the healthy weight range for your height, multiply your height squared by 18.5 and by 22.9.
BMI was proposed in the nineteenth century by the Belgian statistician Adolphe Quetelet, who noticed that among adults, weight tends to rise roughly with the square of height rather than in direct proportion. Dividing by height squared therefore gives a number that stays fairly steady across tall and short people of similar build. It is an empirical choice, not a law of biology. Very tall people tend to score slightly higher and very short people slightly lower than their body fat would suggest.
Studies across Asian populations found that, at the same BMI, South Asians tend to carry more body fat, particularly around the abdomen, and face a higher risk of type 2 diabetes and heart disease than people of European descent. Indian guidance therefore treats 23 as the start of overweight and 25 as obese, instead of the WHO international 25 and 30. The calculator shows both, and computes your healthy weight range from the Indian band of 18.5 to 22.9.
BMI does not separate muscle from fat, so a muscular athlete can be classed as overweight while carrying little fat. It says nothing about where fat is stored, and fat around the waist carries more risk than fat on the hips. It is not designed for children and teenagers, who are assessed with age- and sex-specific growth charts, or for pregnancy. Treat BMI as a screening number, and speak with a doctor if yours falls outside the normal band.
Vikram, a 38-year-old software engineer in Hyderabad, weighs 72 kg and is 174 cm tall, and wants to see how he fares on both the WHO and Indian scales.
Change height to metres: 174 cm ÷ 100 = 1.74 m
Square the height: 1.74 × 1.74 = 3.0276
Divide weight by the squared height: BMI = 72 ÷ 3.0276 = 23.8
Answer: Your BMI 23.8 kg/m²; Category (India / South Asia) Overweight; Category (WHO international) Normal
Using height in centimetres directly in the formula without converting to metres, which gives a tiny number.
Squaring the weight instead of the height.
Relying on the WHO international cut-offs alone, which can miss raised risk in South Asian adults.
Using the adult formula and categories for children or teenagers.
Reading a high BMI in a very muscular person as proof of excess fat without checking waist size or body fat.
A quick self-check before or after a lifestyle change.
Screening in clinics, health camps and corporate health check-ups.
Setting a sensible target weight range for your height.
Tracking weight change in a way that accounts for height.
Why does India use different BMI cutoffs?
Studies show that South Asian people tend to have more body fat, and a higher risk of diabetes and heart disease, at a lower BMI than the WHO's international ranges assume. So Indian guidance treats a BMI of 23 or more as overweight, instead of 25.
Is BMI a reliable measure of health?
It is only a rough screening tool. BMI cannot tell the difference between muscle and fat, and does not show where fat is stored on your body. So athletes may show as overweight, while someone with a normal BMI might still carry extra fat around the stomach. Waist size often gives more useful information.
Why doesn't this calculator ask for my sex, when other health calculators do?
BMI uses the same formula and the same health ranges for both men and women — in WHO, CDC and Indian guidelines. So asking for your sex would not change the result at all. What does change between men and women at the same BMI is body composition — how much of your weight is fat versus muscle. That is exactly what our separate Body Fat calculator measures, using different formulas for men and women.
What should I do if my BMI is outside the normal range?
Treat it as a reason to speak with a doctor, not as a diagnosis. A doctor can look at your BMI along with your waist size, blood pressure, blood sugar and cholesterol to get a much clearer picture of your health than one number alone.