Free calculator
BMI Calculator
Your body mass index from height and weight, with the standard WHO category bands.
- Category (WHO)
- —
Under 18.5 underweight · 18.5–24.9 normal · 25–29.9 overweight · 30+ obese. Some Indian guidelines use lower cutoffs (23 / 27.5).
What BMI tells you — and what it doesn't
BMI is weight in kilograms divided by height in metres squared. It is a quick screening number: useful for populations and a reasonable first check for individuals.
Its blind spot is composition — it cannot distinguish muscle from fat. Athletes often land in "overweight" while being very fit, and it says nothing about where fat sits. Treat it as a starting point, not a verdict.
BMI questions, answered
What is a healthy BMI?
WHO defines 18.5–24.9 as the normal range for adults. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese.
Is BMI accurate for athletes?
Not always. BMI cannot tell muscle from fat, so muscular people can score as overweight while being very fit. It is a screening tool, not a diagnosis.
Are the cutoffs different for Indians?
Some Indian health guidelines suggest lower action cutoffs (around 23 for overweight and 27.5 for obese) because metabolic risk rises earlier in South Asian populations. This calculator shows WHO bands and notes the difference.