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Enter your height and weight to get your BMI, category and guidance in one click.
BMI (Body Mass Index) is your weight in kilograms divided by the square of your height in metres. It is the fastest screening number doctors, gyms and insurers use to classify body weight.
Here is the full classification the calculator uses, based on WHO guidelines:
| BMI Range | Category | What it suggests |
|---|---|---|
| Below 18.5 | Underweight | May need nutritional support |
| 18.5 – 24.9 | Normal weight | Healthy range — maintain it |
| 25.0 – 29.9 | Overweight | Diet and activity review |
| 30.0 and above | Obese | Professional guidance advised |
Your BMI is a starting point, not a verdict. Trends matter more than a single reading — measure monthly, not hourly.
If you know your height in feet and inches, convert it to centimetres: multiply feet by 30.48 and inches by 2.54. For example, 5'7" = (5 × 30.48) + (7 × 2.54) = 170.18 cm. You can also use our free unit converter.
BMI does not distinguish muscle from fat. Athletes and bodybuilders often classify as “overweight” despite low body fat.
It is not calibrated for children (who need age-specific percentile charts), pregnancy, or adults over about 65 without adjustment.
Asian populations sometimes develop health risks at slightly lower BMI values; many Indian doctors use 23 as the overweight cut-off. Use BMI as one signal along with waist size, blood pressure and blood tests.
The standard WHO bands (18.5 to 24.9 as normal) were derived largely from European populations. Research compiled by a WHO expert consultation in 2004 found that Asian populations develop metabolic risks — diabetes, hypertension, heart disease — at lower BMI levels. For Asian Indians, the widely used clinical guidance is: below 18.5 underweight, 18.5 to 22.9 normal, 23 to 24.9 overweight (increased risk), and 25 or above obese.
This matters in practice: a BMI of 24 is labelled normal on international bands but already signals elevated risk for South Asians. Indian medical guidelines and many doctors now apply these lower thresholds when counselling patients.
BMI cannot tell muscle from fat — a fit athlete with heavy muscle mass can score overweight, while someone with low muscle but high visceral fat can score normal. It also says nothing about where fat sits on your body, and visceral (belly) fat is the metabolically dangerous kind. For South Asians especially, fat tends to gather around the abdomen even at normal BMI — sometimes called TOFI (thin outside, fat inside).
A practical companion measure is waist circumference: for Indian adults, risk increases above roughly 90 cm in men and 80 cm in women. Use BMI as a quick screening number, not a diagnosis — a doctor combines it with waist size, blood pressure, and blood tests for the real picture.
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