The county record, an earlier listing and a new appraisal can report different square footage for the same home. Comparing the figures means checking what each includes, how it was measured and which standard applies.
Why measurements differ
Square-footage figures depend on the measurement rule and the areas included. Compare those definitions before using a county, listing or appraisal figure to describe the home.
Where each number comes from
- The county record exists for assessment. It is often built from exterior dimensions and permit history, and it is not re-measured every year.
- An old listing reflects whatever the previous agent entered, from whatever source they had, under whatever the rules were then.
- An appraisal is measured on site by a licensed appraiser, to a written standard, for a lender who is deciding how much to lend.
Check the measurement method and included areas behind each figure before deciding that a discrepancy is an error.
The rule that governs the appraisal
For most conventional loans the appraiser measures to ANSI Z765-2021. Fannie Mae made that standard a requirement, so the rule is no longer a matter of local habit.
Source: Appraisal Institute, "Fannie Mae Adopts ANSI Standard for Square Footage Measurements," reporting the requirement as effective 1 April 2022 for appraisals involving interior and exterior inspections (Fannie Mae Selling Guide B4-1.3-05 and B4-1.2-01). Verified at source 14 September 2026.
What that standard actually counts
Two provisions surprise people more than any others. Ceiling height: finished area has to have a ceiling at least seven feet high. Where the ceiling slopes, at least half the finished area of the room must reach seven feet, and no part of it may be under five feet.
Anything that fails those tests gets reported separately rather than counted with the rest.
And grade. Any level that is even partly below ground is reported as below grade area, not as part of the finished square footage above it. A floor counts as partly below grade if any portion of its walls is not entirely at or above ground level.
Source: Fannie Mae, "Standardized Property Measuring Guidelines" (singlefamily.fanniemae.com), on ceiling height, sloped ceilings and below grade reporting under ANSI Z765-2021. Verified at source 14 September 2026.
Which is why the basement is usually the argument
Finished below-grade space is reported separately under the measurement approach described here. Separate reporting does not by itself establish the space's value, which is part of the property's appraisal.
A headline square-footage figure that includes a walkout level may differ from the appraisal's above-grade figure. Resolve that distinction during listing preparation so the house is described consistently.
Why I measure it before we price anything
I scan every listing myself, and I will tell you what the floor plan shows before we talk about a price. Scanning is part of taking a listing, every listing, every time, and it is never billed separately. The floor plan and the walkthrough are embedded in the MLS listing.
The practical result is that the measurements come from the house rather than from a record somebody else typed, and the ceiling heights and grade changes that decide the number are visible before they become an argument.
Ask the county assessor about correcting the county record and any assessment effect. The lender can address the effect on a particular loan, and an attorney can advise on a measurement dispute after closing.
What belongs to me is the house as it actually is: measured, drawn, and described the same way in every place a buyer will look.
How a house gets measured, drawn and marketed once it is ready is on the listing marketing page. If the question underneath this is whether to sell at all, the Lifestyle Calibration page is where that starts.
This note describes measurement standards in general terms. It is not an appraisal, not tax advice, and not a statement about any particular property. What governs your loan is the standard your lender and appraiser actually apply.