Body Mass Index (BMI) is the most widely used screening tool for assessing whether a person's weight is appropriate for their height. While it does not directly measure body fat, it correlates well with body fat levels and is a useful first indicator of potential health risks. For Indians, however, the standard BMI cut-offs need adjustment — South Asians face metabolic risks at lower body weights than Western populations.
This guide explains how to calculate BMI, the Indian-specific cut-offs, the importance of waist circumference, and worked examples. Check your own BMI with our BMI Calculator.
BMI is a ratio of weight to height squared. It gives a single number that helps classify a person as underweight, normal, overweight, or obese. The formula was developed in the 1830s by Adolphe Quetelet and remains the standard because it is simple, non-invasive, and applicable across populations.
BMI = Weight (kg) / Height (m)²
If you know your weight in kilograms and height in metres, square the height and divide. If your height is in centimetres, convert to metres by dividing by 100.
Weight = 70 kg, Height = 170 cm = 1.70 m
This falls in the overweight category for Indians (23-24.9).
Weight = 55 kg, Height = 158 cm = 1.58 m
This is in the healthy range for Indians (18.5-22.9).
Weight = 48 kg, Height = 165 cm = 1.65 m
This is below 18.5, indicating underweight. A dietitian consultation is advisable.
The WHO global classification differs from the cut-offs recommended for Asian Indians by the WHO Western Pacific Region and India's ICMR:
Why the difference? Indians tend to carry more visceral (belly) fat and less muscle mass than Caucasians at the same BMI. This means metabolic diseases like type 2 diabetes, hypertension, and heart disease appear at lower BMIs in Indian populations. An Indian at BMI 24 might face the same risk as a European at BMI 28.
BMI alone does not distinguish between fat and muscle, nor does it tell you where fat is stored. Central (abdominal) obesity is a stronger predictor of metabolic disease than BMI, and Indians are particularly prone to it. The recommended waist circumference cut-offs for Indians are:
These are stricter than the global cut-offs of 102 cm (men) and 88 cm (women). A person with normal BMI but high waist circumference still carries significant metabolic risk — a pattern called "thin-fat" phenotype common in Indians.
For those under 18, BMI is interpreted using age- and sex-specific percentile charts rather than fixed cut-offs. A BMI between the 5th and 85th percentile is considered healthy, 85th-95th is overweight, and above 95th is obese. Below the 5th percentile indicates underweight. Always consult a paediatrician for child assessments.
BMI is a screening tool, not a diagnostic one. It does not account for:
For a complete picture, pair BMI with waist circumference, body fat percentage, and blood tests.
BMI = weight in kg divided by height in metres squared. For a 70 kg person who is 1.70 m tall, BMI = 70 / (1.70 × 1.70) = 24.2.
For Indians, a BMI between 18.5 and 22.9 is considered healthy, 23 to 24.9 is overweight, and 25 or above is obese. These cut-offs are lower than the WHO global standard because Indians carry more body fat at lower BMI.
Indians and South Asians are genetically prone to central obesity and insulin resistance at lower body weights. Studies show metabolic risk rises earlier, so the WHO and ICMR recommend lower BMI thresholds for this population.
BMI is a quick, useful screening number, but for Indians the standard global cut-offs understate risk. Use the Asian Indian thresholds (overweight at 23, obese at 25), and always check your waist circumference alongside. Calculate yours with our BMI Calculator and explore related tools to manage your overall health and finances.
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