Net internal area (NIA) (or usable floor area UFA) - The NIA is the GIA less the floor areas taken up by lobbies, enclosed machinery rooms on the roof, stairs and escalators, mechanical and electrical services, lifts, columns, toilet areas (other than in domestic property), ducts, and risers.

Use this quick tool to look up the internal area of a property using the latest energy performance certificate from the Ministry of Housing, Communities and Local Government database. EPC floorplans are carried out to a higher standard than agent floorplans - the latter often overestimate true floor area by 10% or more.