Methods of Real Property Measurement | Study.com (2024)

To calculate square footage, measure the distance between the opposing walls, then multiple these measurements. For example, let's assume we are measuring the square room below.

12 X 12 = 144 square feet

Now, let's assume we are measuring a more complicated shape, such as the room below.

In this case, we would take two measurements and then add them together.

(12 X 12) + (8 X 8) = 208 square feet

Gross Building Area (GBA) is a method of real property measurement that takes the exterior measurement and includes the entire finished area and common areas, such as stairways and hallways. However, exterior common areas, such as stairways are not subtracted from the exterior measurement if applicable. The GBA is the most common measurement method used for comparison for two-unit to four-unit family properties.

Gross Living Area (GLA) is a method of real property measurement that uses the exterior building dimensions per floor to determine the above-grade gross living area. Condominium measurement is based on interior perimeter dimensions.

This measurement method excludes basem*nts, attics, and garages, even if they are finished. When reporting the GLA, the finished above-grade room count is included with the square feet of GLA. The GLA is the most common measurement for single-family properties.

American National Standard Institute (ANSI) is a real property measurement method that starts with the outside dimensions and then subtracts the garage; basem*nt; opening to the floor below; any area that does not have a ceiling height of at least seven feet; ceilings under beams, ducts, or obstructions that are not at least six feet four inches; sloped ceilings that are not at least one-half of the finished square footage of the room; and any area with a ceiling height of five feet or less.

Finished areas connected to the main body of the house are included. Finished areas where the main house cannot be accessed without going outside is not included in the square footage. The ANSI is the most common method used by real estate agents.

There are common real property measurement methods; the Gross Building Area (GBA), Gross Living Area (GLA), and the American National Standard Institute (ANSI). The methods differ by what they include as living area. The GBA is the most common method for the measurement of two to four-family units and includes the measurement of all interior areas. The GLA is the most common measurement for single-family homes and excludes the basem*nt, attic, and garage. Lastly, the ANSI is the most common method used by real estate professionals and excludes the basem*nt, attic, garage, and areas under specified ceiling heights.

To calculate square footage for a square or rectangle room, multiply the length by width. For rooms with a triangle shape, the formula is height X base / 2, and for circles such as a foyer, $\pi\ R^2$ and R / 2 for a semicircle such as a bay window.