What is the BMI Calculator?
Body Mass Index (BMI) is a quick screening number that estimates whether your weight is healthy for your height. It's not a diagnosis — but it's the first metric every doctor uses to flag risk for diabetes, heart disease and joint stress.
For South Asian adults, the WHO recommends slightly lower cut-offs: overweight starts at 23 (not 25) and obesity at 27.5 (not 30).
Formula
- Weight — In kilograms
- Height — In metres (cm ÷ 100)
Ranges: <18.5 underweight · 18.5–24.9 normal · 25–29.9 overweight · ≥30 obese.
Step-by-step example
Setup: 70 kg, 172 cm.
- Height in m = 1.72
- BMI = 70 / 1.72² = 70 / 2.9584 = 23.66
Answer: BMI = 23.66 (Normal under WHO, Overweight under Asian cut-offs)
Frequently asked questions
Is BMI accurate for athletes?
Not really — muscle weighs more than fat, so athletes often show 'overweight' BMI without excess body fat.
Should I use Asian cut-offs?
If you have South or East Asian ancestry, yes. Risk for metabolic disease rises at a lower BMI than for Europeans.