Definition
The Gross Usable Area (GUA) is the reference measurement of the French tertiary letting market. It is the surface on which rents, charges and occupancy ratios are calculated. When a real estate agent announces "500 sqm available", they are speaking in GUA.
Specifically, GUA measures the floor area between the interior faces of the building's external walls at each level. It includes office spaces, private internal circulation areas (corridors), private toilets, accessible technical rooms and private common spaces (kitchen, meeting room). It excludes structural elements: load-bearing walls, stairwells and lift shafts, technical ducts, terraces and balconies.
GUA must not be confused with Net Usable Area (NUA), which is the area that is actually "occupiable": GUA minus circulation areas, toilets and technical rooms.
How GUA is calculated (step by step)
The calculation of GUA follows a logic of subtraction from the total building area.
Step 1: Start from the total gross floor area (SHOB). This is the total area of all floors, measured at the outer face of external walls. It includes everything: walls, staircases, ducts, terraces.
Step 2: Subtract structural elements. External and load-bearing walls, stairwells and lift shafts, technical ducts (ventilation, electricity, plumbing), non-enclosed spaces (terraces, balconies, loggias).
Step 3: The result is the GUA. The area between the interior faces of the external walls, after deducting structural elements.
GUA, NUA, SDP: not confusing the surface area definitions
The tertiary real estate market uses several surface area definitions. Mixing them up risks paying for sqm you are not using, or underestimating your actual needs.
GUA (Gross Usable Area): the market reference for letting. This is the one that appears in listings and on which rent is calculated. It includes internal circulation areas, toilets and private technical rooms.
NUA (Net Usable Area): the area that is actually "furnishable", where you can install workstations, meeting rooms, a kitchen. This is the area that matters to you as an occupant.
SDP (Surface De Plancher / Planning Floor Area): the regulatory reference for planning permissions (building permits, prior declarations). Defined by Article R. 111-22 of the French Urban Planning Code. Broader than GUA (it includes certain elements that GUA excludes).
Why it matters: a landlord who announces 400 sqm in GUA is actually offering 300 to 340 sqm of NUA. If you need 40 workstations at 8 sqm/workstation (i.e. 320 sqm of NUA), you need to look for premises of 375 to 425 sqm in GUA. Confusing GUA and NUA means finding yourself cramped from the very first day.
Is your GUA under-utilised? Estimate the revenue potential of your excess sqm with our savings simulator.
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