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The median one-family house on the Travis Central Appraisal District roll is 1,246 square feet in ZIP 78721 and 3,679 square feet in 78730. That is a gap of 2,433 square feet, a factor of almost three, between two mailing areas on the same county roll. Across all 306,832 houses we counted, the median is 2,021 square feet.
If you are searching "how to find the square footage of a house," this is the other half of the answer. Before you can check a number, it helps to know what a normal number looks like where you are looking.
Ten ZIP codes, side by side
| ZIP | Houses | Middle half (25th to 75th) | Median | Under 1,400 | 3,000 or more | Median year built |
|---|---|---|---|---|---|---|
| 78721 | 3,249 | 1,008 to 1,644 | 1,246 | 61.1% | 1.8% | 1972 |
| 78702 | 6,324 | 997 to 1,864 | 1,314 | 55.1% | 3.1% | 1969 |
| 78745 | 14,381 | 1,209 to 1,748 | 1,453 | 44.8% | 1.9% | 1976 |
| 78751 | 3,045 | 1,059 to 2,093 | 1,460 | 47.1% | 6.1% | 1947 |
| 78757 | 6,701 | 1,260 to 2,062 | 1,616 | 34.8% | 5.0% | 1961 |
| 78704 | 7,627 | 1,320 to 2,481 | 1,850 | 28.7% | 12.5% | 1964 |
| 78703 | 4,930 | 1,887 to 3,705 | 2,690 | 10.8% | 41.8% | 1950 |
| 78731 | 6,719 | 2,218 to 3,393 | 2,742 | 4.4% | 38.6% | 1975 |
| 78746 | 8,106 | 2,585 to 4,518 | 3,420 | 0.9% | 62.0% | 1986 |
| 78730 | 2,375 | 3,076 to 4,361 | 3,679 | 0.6% | 78.1% | 1998 |
Two things stand out. First, the medians are wide apart, but the "middle half" column shows the ZIP median hides as much as it tells. In 78704 the middle half of houses runs from 1,320 to 2,481 square feet, so a buyer there is shopping among houses that differ by nearly a thousand square feet before they look at a single listing. In 78751 the range is 1,059 to 2,093.
Second, the year-built column does not explain the size column. 78703 has a median build year of 1950 and a median size of 2,690 square feet. 78745 has a median build year of 1976 and a median size of 1,453. Age and size move separately, because of what has been built and rebuilt since.
Same ZIP, two kinds of house
Several central ZIP codes hold two generations of houses side by side: the original post-war stock and houses built since 2015. We split the same records at those two lines.
| ZIP | Built before 1960 | Built 2015 or later | Difference |
|---|---|---|---|
| 78704 | 1,500 (3,112) | 2,680 (1,616) | +79% |
| 78757 | 1,479 (2,991) | 2,632 (876) | +78% |
| 78702 | 1,140 (2,885) | 1,823 (1,670) | +60% |
| 78721 | 1,064 (773) | 1,660 (824) | +56% |
| 78751 | 1,326 (2,332) | 1,996 (341) | +51% |
| 78745 | 1,288 (1,265) | 1,884 (1,135) | +46% |
In 78702, 1,670 of 6,324 houses on the roll, 26.4%, were built in 2015 or later, and the median new one is 1,823 square feet against 1,140 for a pre-1960 one. In 78704 the newer houses are 79% larger at the median. The roll does not say why, and we are not claiming a cause. It does say that in these ZIP codes the number of square feet depends heavily on which side of 2015 a house falls.
That is the same turnover you can see in the permit record. The City of Austin issued 360 one-family demolition permits from Jan. 1 to Oct. 16 this year, most for houses built before 1960, and 909 remodel and addition permits from Jan. 1 to Sept. 27. A house in one of these ZIP codes may be the original size, an expanded version of it, or a replacement.
How to check the number on one house
The appraisal roll is a good first look and a poor final answer. Here is the sequence we would use.
- Pull the district's record. Travis CAD publishes a property search. Its FAQ says that "the house is measured, classified, and depreciated due to its condition and age," so the district does its own measuring, and that corrections to appraisal records "may affect value, such as a change in square footage" (Travis CAD FAQs, read October 27, 2026). The FAQ also says a building permit for an added room can prompt a district inspection.
- Compare it with the listing. If the number you are shown for a house is much larger than the district's, ask your agent where each came from and when. A house that was added onto after the district last measured it can be larger than the roll says, and a number that includes space the district leaves out can be larger too. We do not know the district's exact rules for what counts as living area, so ask the district.
- Look up the permit history. An addition or a garage conversion should leave a City of Austin permit. Our count of remodel and addition permits shows what those records look like.
- Measure it. If square footage matters to your decision, ask a licensed appraiser or a measuring professional, and ask your agent how your contract treats a difference. We cannot tell you what it will say about yours.
If the district's record looks wrong for a house you own, the FAQ points you to the district's contact page. A square footage correction can change the value on your notice, up or down, so read your notice before you call.
What this means if you're buying, selling or renting here
If you are buying. Use the table as a sanity check. A "small" house in 78746 and a "small" house in 78721 are different sizes. The middle half in 78746 starts at 2,585 square feet, and the middle half in 78721 ends at 1,644. Compare houses on cost per square foot only after you know which square feet each number counts, and ask for the permit history on anything that has been added to. Older houses in several of these ZIP codes sit on pier and beam foundations, which is its own inspection question: see our foundation repair permit count.
If you are selling. Check the district's record for your house before a buyer does. If you have added space and the district's number is older than the work, a buyer's agent will see the mismatch first. Keep your permit paperwork together. We make no claim about what any size does to a price.
If you are renting. The roll covers houses, not apartments, townhomes or condos. A size in a rental listing comes from the listing, not from this roll. The same habit works: ask where the number came from.
These numbers describe buildings and lots in a mailing area. They say nothing about the people in them, and a ZIP code is not a neighborhood. Only the Travis County roll is counted here, so houses on the Williamson and Hays rolls are not in these figures.
How we counted
Source: the 2026 Travis Central Appraisal District roll, as stored in the Zabalist research database (research.cad_improvements, loaded October 7, 2026; the parcel layer it joins to was fetched October 5, 2026). We kept records typed "1 FAM DWELLING," one main improvement per parcel, with a year built after 1800 and a living area between 300 and 12,000 square feet. That kept 306,832 of 307,119 one-family records. ZIP is the ZIP on the record's situs address, and the table shows ZIP codes with at least 1,500 such records. Medians, quartiles, shares and percent differences are our arithmetic on those records. Townhome, condominium and two-family records are excluded. The roll is the district's own measurement for appraisal; it is not a survey, a plat or a listing, and no MLS data was used. This is general information, not advice about a specific property.
One next step
If you are looking at a particular house, a local agent can pull the district record and the permit history next to the listing and walk through any gap with you. Start at our get started page.