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Six Considerations When Calculating Finished Square Footage

Making sure finished square footage is accurate and consistent is important to the integrity of NorthstarMLS listings. The following is a compilation of common questions and discrepancies the NorthstarMLS Rules and Regulations encounter to keep in mind as you create your listings.

July 20, 2023

  1. “Finished” is defined as areas that have finished flooring, wall coverings and ceilings.
    In addition to seeing installed carpet or solid surface flooring, sheetrock or paneling for walls and solid or drop ceilings, areas included in finished square footage should also have permanent, sufficient heating and adequate ceiling height (see #3 below for more on ceiling height).

    Tricky areas to consider are three-season porches and other unheated spaces. Unless they have a permanent heat source (confirm the types of heating local code allows) don’t include these spaces in your finished square footage calculations.

  2. Your listing should show finished square footage for above and below ground.

    When creating a listing in Add/Edit you are asked to distinguish finished square footage both above ground and below ground. Here’s how to measure both:

    Above Ground Finished Square Footage is the total finished square footage measured at and above ground level as it appears from the front view of the building.

    Below Ground Finished Square Footage is measured below ground level as it appears from the front view of the building.

    When calculating, make sure the interior of the home makes sense according to its exterior and the foundation size.

  3. Ceiling Height is also a factor.

    Level ceilings must be at least seven feet high and at least six feet four inches under beams, ducts and other obstructions. There is no height restriction under the stairs.

    If a room has a sloped ceiling, at least one-half of the finished floor area must have a ceiling height of at least seven feet. Otherwise, omit the entire room from the floor area calculations. If a room with a sloped ceiling meets the one-half-of-floor-area-over-seven-feet requirement, then include all the floor space with a ceiling height over five feet.

    Lofts and finished attics must be accessible by a conventional stairway or other access to be counted. If you can only reach the loft by climbing a ladder or going outside, it’s not part of the finished floor area regardless of the ceiling height.

    Check your local building codes for any additional ceiling height measurement or accessibility requirements.

  4. Secondary structures can be included.

    Fully Finished secondary structures such as a carriage house or pool house (with permanent sufficient heating) can be included in the total finished square footage field. However, the size of the secondary structure must be included in the remarks or supplements because appraisers may need to know the size of the secondary unit for valuations.

  5. Consider what makes a floor “finished.”

    Agents often ask if a cement floor can be represented as finished. It is important to consider intent, design, and ensuring accurate representations under the law and REALTOR Code of Ethics.

    Consider these examples:

    In a condo where its glossy cement floor was designed and finished to look like that, the representation that the condo floor is “finished” would likely hold up to a claim of misrepresentation.

    In contrast, a basement where the walls and ceiling are finished but the cement floor remains, it may be more difficult to defend that space as finished.

    An appraiser can provide more specific examples of what would and would not be acceptable in different municipalities or to different lenders. Your brokerage may also have direction to help avoid claims of misrepresentation when representing finished square footage.

  6. Don’t forget what to include in foundation calculations.

    NorthstarMLS Add/Edit also requires that you provide foundation size calculations. When determining foundation size, the basement area, crawl space or any portion of structure that is anchored in the ground with livable space above it are included in your calculations.

    In most cases, the foundation should not exceed the below ground square footage. Normally garages and porches are not factored into the foundation size. Exceptions in those cases would be if the garage has livable space above it, like a tuck under garage or converted attic space. Click here for more information about foundation calculations.

The NorthstarMLS team is here to help. For more information about calculating finished square footage, check out our video on the Basics of Measuring.

You can also visit our Rules + Regs site or contact us at

By Mandy Boldt

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