The biggest house in our data had the smallest bill.
Every calculator that asks for your square footage and returns a renovation estimate is doing something our own numbers say does not work. We went back through 16 completed renovations across 13 states, 1,413 priced line items and $510,224 of scope, and size explained about two percent of what the work cost. Here is the data, and what to do instead.
$2.85 to $74.25 a square foot. Same company, same year.
These are finished bills on completed jobs, not quotes. Each row is one house, anonymised to its state and size, because they belong to sellers rather than to us.
| State | Size | Final cost | Per sq ft |
|---|---|---|---|
| HI | 1,690 sq ft | $125,490 | $74.25 |
| GA | 680 sq ft | $30,607 | $45.01 |
| CA | 1,844 sq ft | $48,890 | $26.51 |
| TX | 1,260 sq ft | $32,282 | $25.62 |
| AZ | 1,666 sq ft | $35,952 | $21.58 |
| CO | 2,240 sq ft | $37,675 | $16.82 |
| NC | 1,802 sq ft | $26,935 | $14.95 |
| CT | 1,112 sq ft | $13,250 | $11.92 |
| WA | 1,398 sq ft | $15,807 | $11.31 |
| GA | 2,448 sq ft | $21,861 | $8.93 |
| NY | 2,668 sq ft | $23,594 | $8.84 |
| OK | 2,316 sq ft | $13,220 | $5.71 |
| MD | 2,750 sq ft | $7,840 | $2.85 |
The 1,690 square foot home in HI cost $125,490. The 2,750 square foot home in MD — over a thousand square feet larger — cost $7,840. If size drove cost, that could not happen. Across the set, size and total cost were very slightly negatively related.
The first estimate moves, and not in one direction.
Of the 13 deals that got past a first draft, 10 moved by more than 20%. Five went up and seven came down. That is not a company being optimistic, and it is not one that can be corrected with a fudge factor — a model tuned to add twenty percent would have been wrong on every deal that came down.
The two directions are different things happening. Upward is scope nobody could see from the kerb: what is behind the wall, under the carpet, on the roof. Downward is scope being cut to keep the job worth doing. Both are normal. Neither is visible in a per-square-foot number.
What that means for you.Any first figure you are given for renovation work, by us or anyone else, is a starting position. The useful question is not “what is the number” but “what happens to it when somebody actually looks, and who carries that.”
The comparison worth making is on your address, not on an average.
Selling as-is trades some price for certainty and speed. Fixing up trades time and risk for a higher asking price. Which one wins is a question about your particular house and the particular work it needs, and the data above is the reason no general rule survives contact with it.
Zoom Casa’s net sheet runs on your address and shows what you would net, line by line, before we ask how to reach you. If the work your house needs is small, it will tell you that. We would rather you saw the arithmetic than took our word for it.
If you would rather read how a cash offer is put together first, our guide to checking a cash buyer covers the questions worth asking, and our pre-sale prep programme is the version where the work happens before the sale.
Where these numbers came from.
Nineteen Zoom Casa renovation deals were sourced from completed project files. Sixteen carried enough structure to use, across 13 states, covering 1,413 individual priced line items and $510,224 of scope in total. Every figure on this page is a final billed amount from that set. Thirteen of the sixteen had more than one proposal version, which is what makes the drift measurable.
Sixteen is a small number, and we are not going to dress it up. It is enough to demonstrate that a per-square-foot rule fails, because a single counterexample does that and we have several. It is not enough to give you a reliable average, which is exactly why this page does not offer one. When the sample grows, the page gets updated rather than quietly left to age.
What sellers ask about this.
How much does it cost to fix up a house before selling?
Across 16 completed Zoom Casa renovations in 13 states, the finished bills ran from $7,840 to $125,490. Cost per square foot ranged from $2.85 to $74.25 — a 26-fold spread — which is why a per-square-foot estimate is not an estimate. What drives the number is the specific work the house needs, not how big it is.
Is cost per square foot a reliable way to estimate renovation cost?
No, and we can show the working. Across our 16 deals, size explained about 2% of the variation in cost, and the relationship was very slightly negative. The largest home in the set, at 2,750 square feet, carried the smallest bill at $7,840. Any tool that asks only for an address and a square footage is guessing, however confident it looks.
Why do renovation quotes change after the first estimate?
Because the first estimate is made before anyone has been through the house. Of the 13 deals that got past a first draft, 10 moved by more than 20%, and they moved in both directions — 5 up and 7 down. Upward is usually scope discovered once someone is on site. Downward is usually scope cut to keep the deal viable. There is no single correction factor that would have fixed either.
Should I sell as-is instead?
That depends on the size of the work and what it would return, and the honest answer is that nobody can tell you from a square footage. Selling as-is trades some price for certainty and speed. The way to decide is to see both numbers side by side for your actual address rather than reason about averages.
How big is this sample?
Sixteen completed deals across 13 states, drawn from 19 sourced, covering 1,413 priced line items and $510,224 of scope. That is a real sample for a claim this specific and a small one in absolute terms, and both of those are true at once. We would rather publish the number we measured than an average we did not.
Net-sheet previews are illustrative; final offer terms are issued in writing on a term sheet. Program availability varies by state. Past results don't guarantee future outcomes — not all properties qualify.