Health Calculators

Every formula here is published and named: Mifflin-St Jeor for metabolic rate, the US Navy tape method for body fat, the WHO bands for BMI alongside the lower Indian cut-offs that ICMR uses. Each page says what the formula is, how accurate it is, and where it stops being appropriate.

That last part matters more than the number. BMI cannot tell muscle from fat and was built on European populations; Indians carry more body fat at the same BMI, which is why the overweight line here starts at 23 rather than 25. Body fat from a tape is accurate to three or four points, not one. Water intake has no clinical formula at all, and eight glasses a day was never based on anything.

None of this is medical advice and none of it knows your history, your medication or the fact that it is 42 degrees outside. Treat a result as something to raise with a doctor, and if it conflicts with advice you have been given, the advice wins.