Does a walkout basement count as square footage in New York?
No, a walkout basement does not count as square footage in New York.
Not as gross living area, in New York or any other state. A walkout basement is open to the ground on one side but still buried on the others, and ANSI Z765 puts any level with part of it below ground in the below-grade column. It is reported as finished below-grade area and valued separately, usually higher than a standard basement. Fannie Mae requires that standard everywhere, so the answer does not change at the New York line.
Why a walkout basement is not gross living area in New York
The walkout side does not rescue the level. ANSI Z765 asks one question: is any part of this floor below the ground on any side? For a walkout the front or side walls are still below grade, so the whole level is below grade. That is why the answer is the same on a sloped lot in New York as on a flat one. The one exception is a lower level that sits entirely above ground on every side, which is a fact about the lot, not the design.
Where a walkout does differ is value. Full-height windows, a door at grade, and a patio make the space feel like a lower level, and in markets where buyers pay close to above-grade prices for it, the appraiser supports a larger below-grade adjustment. The square footage still sits on the below-grade line.
Basements in New York homes: the numbers
In New York, 85% of single-family homes sit over a basement, according to the 2024 Residential Energy Consumption Survey, against 43% nationwide. That share is about the same as in the 2020 survey.
Of those basements, 49% are finished. Every square foot of that finished area is measured by an appraiser and reported as below-grade finished area, never as gross living area.
Here is the number that explains the arguments: 28% of New York owners with a basement include it when they report their home's square footage. Nationally it is 40%. Under ANSI Z765, none of them should, which is why an owner's number and an appraiser's number so often disagree.
The average New York single-family home has 2,377 square feet of total area, basement included, compared with 2,248 nationally.
| Single-family homes | New York (2024) | United States (2024) |
|---|---|---|
| Have a basement | 85% | 43% |
| Basements that are finished | 49% | 59% |
| Owners who count the basement in their square footage | 28% | 40% |
| Average total area, basement included | 2,377 sq ft | 2,248 sq ft |
Source: U.S. Energy Information Administration, Residential Energy Consumption Survey. Values are for single-family homes; a small number of states have samples too small to report every line.
Calculator: what a walkout basement adds to a New York house
Enter the walkout basement area and the above-grade area. The first figure is the gross living area an appraiser reports; the last is the inflated number a listing shows when it adds the basement in.
The walkout basement does not count. The appraisal GLA stays at 1,800 square feet. A listing that adds it in would show 2,600, which overstates the house by 44%.
How Northeast basements changed since 1971
New York is in the Census Bureau's Northeast region. In 1971, 80% of new single-family houses completed in the Northeast were built with a full or partial basement. In 2025 it was 53%. Nationally the share went from 36% to 16% over the same years, as slab and crawl-space construction spread.
What to put on a New York listing
Report the above-grade area as the square footage and the walkout basement on the below-grade or "finished basement" line your MLS provides. Most New York listing systems have separate fields for above-grade, below-grade, and total finished area. Filling in the total field is fine; presenting it as the size of the house is what causes appraisal gaps and, in some states, complaints.
If a buyer's appraisal comes in with a smaller number than the listing, this is almost always the reason. The house did not shrink. The basement moved to the line where ANSI Z765 puts it.
Frequently asked questions
Does a walkout basement add to square footage in New York?
It adds value and it adds below-grade finished area, but it does not add to gross living area. New York appraisers follow ANSI Z765 because Fannie Mae requires it, and that standard keeps every basement on a separate line.
Do New York appraisers count a walkout basement?
They measure it, report it as below-grade area, and value it with its own adjustment. They do not count it in GLA. There is no New York exception to the standard.
Does Zillow square footage include the basement in New York?
Often, yes. Zillow and county records frequently show a total that includes finished basement area, and 28% of New York owners with a basement count it in their own figure. An appraisal will show a smaller number because it reports above-grade GLA only.