BMI Calculator
Calculate your Body Mass Index and see where it falls on both the WHO scale and the lower cut-offs recommended for Asian Indians, plus the healthy weight range for your height.
What is the BMI Calculator?
BMI is a screening measure that relates weight to height. Research shows that Asian Indians face higher risk of diabetes and heart disease at lower BMIs, so Indian guidelines use lower thresholds for overweight (23) and obesity (25).
How does it work?
BMI is weight in kilograms divided by height in metres squared. Imperial inputs are converted first.
Formula
BMI = weight (kg) ÷ height (m)²
Example
70 kg at 175 cm: 70 ÷ 1.75² = 22.9 — normal on both scales, just below the Asian-Indian overweight cut-off of 23.
BMI categories for adults
Indian consensus guidelines use lower cut-offs than the international WHO scale, because South Asians tend to develop diabetes, high blood pressure and heart disease at lower body weights. The calculator shows both.
| Category | WHO (international) | Asian Indian guidelines |
|---|
| Underweight | Below 18.5 | Below 18.5 |
| Normal | 18.5 – 24.9 | 18.5 – 22.9 |
| Overweight | 25 – 29.9 | 23 – 24.9 |
| Obese | 30 and above | 25 and above |
Healthy weight for your height
Rearranging the formula gives a healthy weight range: weight = BMI × height². Using the Asian Indian normal range of 18.5 to 22.9:
| Height | Healthy weight range |
|---|
| 150 cm | 41.6 – 51.5 kg |
| 160 cm | 47.4 – 58.6 kg |
| 170 cm | 53.5 – 66.2 kg |
| 180 cm | 59.9 – 74.2 kg |
What BMI does not tell you
- Body composition: muscular people can have a high BMI with little body fat, while some people with a normal BMI carry excess fat.
- Fat distribution: fat around the abdomen carries more health risk. For Indian adults, a waist circumference above 90 cm in men or 80 cm in women indicates higher risk, even with a normal BMI.
- Age and sex differences: older adults naturally lose muscle, and women generally have more body fat than men at the same BMI.
- Children and teenagers: BMI must be compared with age- and sex-specific growth charts, not the adult categories.
- Pregnancy: BMI is not meaningful during pregnancy; pre-pregnancy BMI is used instead.
If your BMI is outside the normal range
Use BMI as a prompt for a conversation with a doctor, not as a diagnosis. A doctor may check blood sugar, blood pressure and cholesterol, and look at waist size and family history before suggesting changes.
For gradual weight loss, a modest calorie deficit combined with regular physical activity is usually recommended. Even losing 5–10% of body weight improves blood sugar and blood pressure in many people.
Frequently asked questions
Why are there two BMI categories?
WHO cut-offs (25 overweight, 30 obese) were based mainly on European populations. Indian consensus guidelines recommend 23 and 25 for Asian Indians.
Is BMI accurate for athletes?
No. Muscular people can have a high BMI with low body fat. Waist circumference or body fat percentage adds useful context.
Is BMI the same for men and women?
The formula and adult cut-offs are the same for men and women. Women typically have a higher percentage of body fat at the same BMI, which is one reason BMI is only a screening tool.
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