🏠 What Does GEA or GIA on Rightmove Really Mean for My Property?

jackindesign
Nov 8
3 min read

Updated: Nov 10

You’re browsing through Rightmove or Zoopla and spot a listing that says:“Floor area: 85 m² (GIA)” or “Measured on a GEA basis.”

It sounds professional — but what does it actually mean for your property? 🤔

Whether you’re buying, selling, or redesigning your home, understanding these measurement codes can make a big difference. Let’s unpack what GEA and GIA mean — and why they matter more than you might think.

📏 What Are GEA and GIA?

Both terms come from the RICS Code of Measuring Practice (6th Edition, 2015) — the industry standard that ensures property areas are measured consistently and fairly across the UK.

Here’s what they mean:

1. GEA – Gross External Area

GEA is the measurement of a building to the external face of the outer walls.It includes everything inside the outer perimeter walls — even external walls themselves, lobbies, plant rooms, and internal walls.

Used for:

Planning applications
Building cost estimation (e.g. construction costs)
Rating assessments for industrial buildings
Property insurance and redevelopment studies

Excludes:

Open balconies, canopies, external staircases, or open-sided covered ways

In simple terms, GEA measures the total footprint of the building, as seen from above, including the thickness of its external walls.

2. GIA – Gross Internal Area

GIA measures the space inside the external walls — from the internal face of the perimeter walls. It includes all internal partitions, corridors, toilets, and storage rooms but excludes external walls.

Used for:

Building design and space planning
Valuations for industrial or warehouse premises
Rentable area calculations in some commercial contexts
Residential property measurement for new build or refurbishment

Excludes:

External wall thickness
External balconies and verandas
Voids over stairwells or atriums

Think of GIA as the total usable floor area within the walls — the space you can design, heat, or occupy.

3. NIA – Net Internal Area

While not part of the main focus here, it’s worth noting NIA is the usable area available to occupants, excluding common areas like lobbies, corridors, and WCs. It’s typically used for offices and lettable commercial spaces, where the focus is on rentable floor space.

Why These Definitions Matter

The difference between GEA and GIA might seem minor, but in practice, it can make a huge difference.For example:

A valuation report or planning application that uses the wrong standard could misrepresent the property’s size.
A developer’s cost plan based on incorrect GEA might lead to significant financial discrepancies.
A designer’s layout based on GIA ensures that interior proportions and circulation spaces are practical and achievable.

By using the correct measurement code, professionals maintain accuracy, transparency, and trust — both with clients and regulatory bodies.

🧱 How the Code of Measuring Practice Helps

The RICS Code of Measuring Practice (2015) defines when to use each measurement standard — ensuring everyone in the industry speaks the same language.

It helps:

Buyers and sellers understand property size fairly
Architects and designers plan accurately
Surveyors and valuers report consistently

At Ro Taste Interiors, we follow RICS standards in every measured building survey. That means our floor plans and layouts are accurate, compliant, and ready for collaboration with architects, contractors, and agents.

Final Thoughts

Next time you see GEA or GIA on a listing or floor plan, you’ll know exactly what it means.GEA tells you the total external footprint, while GIA shows the internal usable area — the space that truly matters for living and design.