Area converter

Área útil counts only the walkable floor of the rooms, measured inside the walls. It is the closest thing to what a British or American listing would call usable or net internal area. Área bruta privativa adds the thickness of the walls and any private balconies, measuring the interior of the dwelling to its outer perimeter. Área bruta dependente is what belongs to you but sits outside the dwelling itself: garage, storage room, loft. And área bruta de construção is the sum of the last two.

It is that last one which appears on the caderneta predial and which the rateable value is built on. It is also the largest of the four, and therefore the one that produces the lowest price per square metre, which explains why some listings prefer it.

This is where terminology turns into consequence. Two genuinely equivalent homes, advertised at the same price, produce different figures per square metre if one divides by the gross construction area and the other by the usable floor area. Anyone setting the two figures side by side concludes that one is dearer than the other, and it is not.

The mistake is commoner than it sounds, because Portuguese listings rarely identify the area they are quoting: a number in square metres appears, without saying which. Before comparing, the question to ask is always the same one, and it is about the metric.

For buyers arriving from a market that quotes in square feet there is a second trap underneath the first. Converting the figure is arithmetic and this page does it for you; knowing which Portuguese area was converted is the part that actually decides whether two properties are comparable, and no conversion will tell you that.

The confusion deepens with outbuildings, enclosed balconies and converted lofts, which may or may not be counted, and which may or may not have been legalised. An area that appears in the listing but not on the caderneta predial is a thread to pull, not a bonus.