One flat is advertised as 80 square metres and another as 74. The first appears larger until you discover that its figure includes a balcony and part of a shared area. The numbers may both be honestly reported, yet still answer different questions.
Before comparing price per square metre, ask what has actually been measured. A neat calculation cannot repair an inconsistent starting figure.
Request the basis, not just the total
Ask the agent for the measurement method, date and source of the figure. Request a breakdown of internal accommodation, balconies, garages, storage and any shared space included. Terminology and reporting conventions differ across markets, so avoid assuming that “gross”, “net” or “saleable” has one universal meaning.
The RICS measurement guidance illustrates why defined measurement practices matter. A reference to a standard is useful only when the listing explains which basis was used; it is not permission to guess the missing details.
Make a comparison that preserves uncertainty
Imagine two fictional listings. Home A reports 80 square metres including a 10-square-metre balcony. Home B reports 74 square metres internally and lists its balcony separately. Do not simply place 80 and 74 in the same “living space” column. Record the published totals and the different inclusions, then obtain comparable figures.
Keep unknowns visible. Write “not confirmed” instead of subtracting an estimated wall thickness or inventing the area of a room from a wide-angle photograph. If an area figure materially affects your decision, seek appropriate local professional measurement or advice.
Also separate total area from useful layout. A long corridor and an awkward corner may count within an agreed measurement while contributing differently to everyday use. A floor plan, an in-person viewing and measurements of important furniture clearances answer questions that a single total cannot.
End your comparison sheet with the outstanding question for each property: “Does this include the terrace?” is more useful than an apparently precise price-per-area ranking built from mismatched definitions. Once the basis is confirmed, the arithmetic becomes meaningful rather than merely tidy.