How BMI is calculated
BMI = weight (kg) ÷ height (m)². For example, 70 kg ÷ (1.70 m)² = 24.2. The result is compared against cutoffs to label it underweight, normal, overweight, or obese.
Your BMI category depends on which cutoff set you use. WHO standard cutoffs are the global default. WHO Asian / South Asian cutoffs are clinically more meaningful for Pakistanis because of higher cardiometabolic risk at lower BMI — the WHO Expert Consultation (2004) proposed considering 23 kg/m² as overweight and 27.5 as obese in Asian adults.
BMI cutoffs side by side
| Category | WHO Standard | South Asian |
|---|---|---|
| Underweight | < 18.5 | < 18.5 |
| Normal | 18.5–24.9 | 18.5–22.9 |
| Overweight | 25–29.9 | 23–27.4 |
| Obese | ≥ 30 | ≥ 27.5 |
When BMI is misleading
BMI does not directly measure body fat. It can over-estimate fat in muscular athletes and under-estimate it in older adults who have lost muscle. For South Asians especially, waist-to-height ratio often picks up risk that BMI alone misses. Use both together.
FAQ
What is BMI?
Body Mass Index (BMI) is a number calculated from height and weight (BMI = weight in kg ÷ height in metres²). It is a population-level screen for under- or over-nutrition. BMI does not measure body fat directly; it is a quick estimate.
What's a healthy BMI for Pakistanis?
Using WHO Asian / South Asian cutoffs (recommended for Pakistanis), a healthy BMI is 18.5 to 22.9. 23 to 27.4 is overweight, and 27.5 or above is obese. These cutoffs are lower than the global standard (25 / 30) because South Asians develop diabetes and heart disease at a lower BMI.
Why do South Asians have different BMI cutoffs?
South Asians (Pakistan, India, Bangladesh, Sri Lanka, Nepal) tend to carry more visceral (abdominal) fat at any given BMI compared with European populations, and develop type 2 diabetes and cardiovascular disease at lower BMI. The WHO Expert Consultation in 2004 proposed lower cutoffs for Asian populations.
Is BMI accurate for athletes or very muscular people?
BMI can over-estimate body fat in muscular athletes (because muscle weighs more than fat) and under-estimate in older adults who have lost muscle. For most non-athletic adults, it is a useful first screen. Combining BMI with waist-to-height ratio gives a more complete picture.
What if my BMI is in the obese range?
Sustained loss of even 5–10% of body weight meaningfully reduces risk of diabetes, heart disease, and joint pain. Speak to your doctor about a screening blood test (fasting glucose, HbA1c, lipid profile, blood pressure). PakVita has a Pakistan-specific weight-loss diet plan and calorie calculator.
Is BMI useful in pregnancy or for children?
BMI is for non-pregnant adults. Children and teens use age-and-sex-specific BMI percentile charts, not adult cutoffs — see our Child Growth Percentile tool. For pregnancy, weight gain targets are based on pre-pregnancy BMI; talk to your obstetrician.