Every number on this page comes from documents anyone can download: deeds, sales filings, tax rolls, permits, zoning. No listings, no paid data vendors, no estimates presented as facts. Pilot area: Brooklyn Community District 2 (Downtown Brooklyn), New York City — 8,115 tax lots, 43,533 unit sales since 2003, 312,933 register documents since 1966.
1. The land price is on the record, and it is a small share of the finished value. For the 74-storey tower at 9 DeKalb Avenue the site deed of December 2015 reads $90,000,000. Against 541 units at today's median sale price the land is about 11% of the implied sell-out, or $194 per buildable square foot of what zoning allowed. Across the 119 buildings completed since 2010 whose site deed we can read, the median land price is $240 per buildable square foot (interquartile range $154–$361). Land bought in 2010–14 cost a median $183 per buildable foot; land bought in 2015–19, $322 — the price of a development site in this district roughly doubled in five years before the towers were finished.
2. Height is paid for, floor by floor. Among condo units sold since 2019, the median price per square foot rises from $1,306 on floors 1–5 to $1,419 on floors 11–20 and $1,634 above the 40th floor: about 25% from bottom to top of the same market. Buildings of 16–30 floors sell at the highest per-foot medians; the tallest band (31+) sits lower because it includes large new buildings still in their first sales cycle.
3. New is worth 20% more than old, and the premium fades within twenty years. Units in buildings five years old or younger sell at $1,507 per square foot; 6–20 years old, $1,265; pre-war buildings (60+ years) at $1,236, essentially the same as middle-aged stock. The age discount is front-loaded.
4. Large units carry a premium, small units a smaller one. Units over 1,300 square feet sell at $1,510 per foot; 600–1,299 square feet at about $1,290; studios under 600 square feet at $1,388. Per-foot pricing is U-shaped in size, which matters for any model that assumes a single price per foot.
5. The district tripled in twenty years, with two plateaus. Condo prices per square foot went from $455 (2003) to $725 (2008), fell to about $600 through 2011, then climbed to $1,258 (2018), paused, and reached $1,494 in 2023. 2024–2026 sit between $1,325 and $1,457 — flat in nominal terms.
These are medians, not causal effects: tall buildings are also new, new buildings are also near the subway. Separating the effects is what the regression in section 3 is for. All figures: arm's-length condo-unit sales, unit area from the assessment roll.
Yes — this page follows a forty-year academic literature, and we checked the specific claims against it (full list with sources in the project repository):
What we did not find in the literature: a public, lot-by-lot presentation that puts the land deed, the unit sales, the zoning pipeline and the model on one page. That gap is the reason this site exists.
ACRIS, the city register, records every deed since 1966 with the price paid. For a tower finished in 2021 we can read the $90,000,000 deed for its site in 2015 and the 2012–2018 deeds for the neighbouring lots that were assembled into it.
The Department of Finance publishes each sale with block, lot and apartment number (2003–today). The assessment roll adds the unit's floor area, so price per square foot is computable for condo units.
PLUTO gives each tax lot its zoning, allowed floor-area ratio, year built, floors and units. Building footprints add roof height. Together they say how much of the allowed envelope was used.
Permit filings (1989–today, daily), zoning applications with their review status, and certificates of occupancy mark each project as disclosed, under review or built.
DOB permits since 1989 · ZAP applications · certificates of occupancy
Medians of arm's-length condo-unit sales 2019–2026 in the pilot area, price per square foot of unit area. Descriptive only — the regression that separates these effects comes next.
Last priced deed on the site in the ten years before completion, divided by lot area × allowed residential FAR. Buildings completed 2010 or later.
Land deed ÷ (median unit price × residential units). Rough by construction: assumes every unit sells at the median; retail and parking excluded.
What a developer paid per square foot of what zoning lets them build. The number that makes land comparable across lots of different size and zoning.
How much of the finished value went to land. With construction cost added: residual = sell-out − land − cost.
No city publishes per-building cost; a published cost index scales a base-year figure. Always labelled as an estimate.
Fitted offline on all arm's-length unit sales; each β is reported with its confidence interval and compared with published estimates. The page then shows, for one unit, how much of its price each term explains. Coefficients not yet estimated.
Difference-in-differences around each zoning change: lots inside the rezoned area vs neighbours outside, three years before and after.
Panel over all 59 community districts, 2003–2026; walk-forward validation, reported against a "same as this year" baseline.
Click a building. Each section opens on demand. Deeds 1966–, unit sales 2003–, permits 1989–.