How is square footage measured for appraisals? The (unfortunate) truth is that it depends on who’s measuring. The correct answer should be: the method for calculating the square footage of a home is determined by the American National Standard Institute (ANSI).

How Is Square Footage Measured

The ANSI standards are taught by the leading appraisal organizations. Many state licensing boards require these standards in an effort to promote uniformity and professionalism in calculating square footage. If you really want to “nerd out” you’re welcome to check out ANSI’s Square Footage Guide.


Real-Life Example: Different Square Footage

Below is a real example of an Appraiser’s response after reviewing the square footage of two different appraisals on the same property. This example is provided for three reasons:

  1. to provide an understanding of how square footage measurements can vary based on an appraiser’s methods,
  2. illustrate the knowledge of a true professional and how to properly measure square footage, and
  3. help you understand the complexity and details of what’s taken into consideration for a home’s square footage.

Appraiser’s Response

I have received the floor plan sketch of the property together with building sketches with Gross Living Area (GLA) calculations prepared by Lazy Linda (4,228 SF) and Better Brenda (3,987 SF). My observations are as follows: Lazy Linda rounded all her measurements to the nearest square foot which is improper appraisal procedure. She should have rounded all dimensions to the nearest 1/10th of a square foot. Lazy Linda’s sketch does not appear to totally follow the floor plan (see rear of garage) and there is no extension off the breakfast room. Also, she rounded the rear building dimension line to 51 feet when it appears to be closer to 50 feet. As a result, this methodology has likely overstated the homes GLA. Lazy Linda’s sketch provides an unacceptable level of detail in ground floor measurements by today’s standards, although she did include stairway areas on the second-floor level.

On the other hand, Better Brenda has properly rounded measurements to the nearest 1/10th of an inch. As you can see, she follows the measurements of the garage and the protrusion area off the breakfast room as noted on the floor plan. I did note that Better Brenda has not included the actual treaded part of the stairway for either of the two staircases in second-floor calculations. These areas should be included according to ANSI Standards for calculating second-floor level stairs. As a result, this would have increased her square footage calculation+/-100 SF.

What’s Next

Mark and the team can walk you through the entire home loan process and mortgage loan process. Call us with any questions and let us know how we can help.


Mark Pfeiffer

Branch Manager
Loan Officer, NMLS # 729612

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