FloorprintSquare footage explained: gross, interior and living area
One house has several correct areas, because they count different things. The words are used loosely in listings, so two figures for the same home can both be honest. This guide explains the common terms in plain language; check the document that applies to you for the official one.
The terms, side by side
| Term | Usually means | Floorprint |
|---|---|---|
| Room area (net) | Each room measured inside its walls | Room area |
| Interior area | Everything inside the outer walls, interior walls included | Interior area |
| Gross area | Measured to the outer face of the outer walls | Gross area |
| Gross living area, GLA (US) | Finished, heated space above ground, usually measured to the outside of the walls | Close to gross area, without garage and basement |
| Gross internal area, GIA (UK) | Floor area measured to the inside face of the outer walls, internal walls included | Close to interior area |
These are descriptions, not definitions. The official wording depends on the source: a standards body such as ANSI in the US, a professional body such as RICS in the UK, your MLS or listing service, a lender or appraiser, or your local government.
A worked example
Take a 40' x 30' house with 6" outer walls. Measured to the outside it is 40 x 30 = 1,200 sq ft, which is the gross area. Measured to the inside of the outer walls it is 39 x 29 = 1,131 sq ft, the interior area. Subtract interior walls and the room area is smaller still. If part of the 1,200 sq ft is a garage or an unfinished basement, a US listing would usually leave it out of the living area. That is a gap of several percent from one house.
Which one to use
For comparing layouts and setting a target in your own planning, use any of them as long as you stay with one. For a listing, a sales contract, a loan or a tax form, use the one that the document or the person asking requires, and measure the way they say. Floorprint's figures are simplified estimates, not an official measurement or legal advice. A surveyor, appraiser or your agent can tell you which definition applies.
More on counting: the square footage calculator and floor plans for listings.
Questions
Which area do listings use?
It depends on the country and the listing service. In many US listings it is a living area measured to the outside of the finished walls above ground, but conventions differ, so check yours.
Why do two measurements of the same house differ?
They measure to different places (inside or outside of the walls) and include or exclude different spaces, such as a garage or basement.
Is gross area the same as living area?
Not exactly. Gross area counts everything to the outer walls; living area usually leaves out garages, unfinished spaces and sometimes basements.
Does Floorprint show the official area?
No. It shows simplified figures from your drawing. Check the rules that apply to you.
Start drawing
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