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The short answer
It counts as finished basement area, not as above-grade living area. Listings often show a total that includes it, but appraisals for Fannie Mae loans report it on a separate line and value it separately.
The ANSI Z765 standard, which Fannie Mae requires appraisers to use, treats any level that is partly or completely below grade as basement. It is reported as below-grade area, finished or not, and is not part of gross living area. The National Association of Realtors notes that a walk-out basement is still not gross living area, though some markets include finished below-grade space by local custom. Finished areas must also have a ceiling of at least 7 ft to count as finished square footage.
Does it still add value?
The National Association of Realtors' 2022 Remodeling Impact Report estimated that converting a basement to living area recovers 86% of its cost at resale: $49,250 of a $57,500 project, according to HGTV's summary. That made it the fourth-best interior project in the report. HomeAdvisor gives a more cautious "up to 70%". Neither figure is a guarantee: appraisers compare your house with recent local sales.
Worked example
The example basement is 32 × 26 ft, 832 sq ft. Leaving out the 120 sq ft furnace room gives 712 sq ft of finished below-grade area. If one 8 × 10 ft section under a sloping stair had a ceiling under 7 ft, another 80 sq ft would come off. None of it becomes above-grade living area.
What appraisers look at in a finished basement
- Whether the space is finished to the same standard as the rest of the house.
- Ceiling height, and whether finished areas reach 7 ft.
- Legal bedrooms with egress openings and a bathroom.
- Walk-out access, which is common in some markets and adds appeal.
- Permits: unpermitted work can be discounted or flagged.
- How comparable recent sales nearby with finished basements were valued.
Listing totals versus appraisals
Real estate listings often show a total finished square footage that includes the basement. The appraisal for a Fannie Mae loan reports above-grade gross living area separately and puts the basement on its own lines for total and finished below-grade area. A buyer comparing two houses by listing totals can be misled when one total includes a basement and the other does not.
Common questions
Does a walk-out basement count as square footage?
Not as gross living area. The NAR notes that any area partly below grade, including a walk-out, is not recognized as GLA, though local custom varies.
Does Zillow count basement square footage?
Listing sites show what the listing agent enters; appraisals follow ANSI and lender rules.
Related calculators
Sources
- https://www.mckissock.com/blog/appraisal/understanding-gross-living-area/
- https://www.nar.realtor/node/194378
- https://nar.realtor/sites/default/files/documents/2022-remodeling-impact-report-04-19-2022.pdf
- https://www.hgtv.com/design/remodel/interior-remodel/basement-remodel-splurge-vs-save