Question

if the SI unit of weight is N (newton), then why we measure our weight in kg????????

Answer 1

actually mass is measured in kilo grams and weight is measured in Newton

Answer 2

There is no difference in ordinary life, either. Nobody wants to buy five Newtons worth of meat, we all want half a kg (in the US that's roughly a lbs, by which we actually mean mass, not weight, it's just a misnomer)