Decimal-Acre Reference / Sheet 0.04
0.04 Acres = 1,742 sq ft
One twenty-fifth of an acre. The lot dimension that put the row house, the brownstone, and the New Orleans shotgun cottage into the American urban vocabulary. The math is exact: 0.04 multiplied by 43,560 equals 1,742.4 square feet, or 161.87 square metres.
Based on the international acre (43,560 sq ft, 1959 IYPA standard).
Square Feet
1,742.4
international ft2
Square Metres
161.87
m2
Hectares
0.0162
ha
Derivation: 0.04 acres × 43,560 sq ft per acre = 1,742.4 sq ft, exactly. The constant 43,560 derives from one chain (66 ft) multiplied by one furlong (660 ft), the surveyor units the 1959 IYPA formalised.
Sheet 02 · The Sub-Townhouse Class
What 1,742 square feet of land produces
A 0.04-acre lot is roughly 14 percent smaller than a 0.05-acre townhouse lot, which is the difference between a 22-foot-wide brownstone and a 19-foot-wide row house on the same depth. That four-foot difference matters at urban scale: a 19-foot frontage forces narrower stair runs, slimmer hallways, and often a different roof structure compared to a 22-foot lot. The buildings that work on 0.04 acres are mostly the historic narrow-frontage typologies that predate the suburban expansion: the Philadelphia trinity, the New Orleans shotgun, the Boston bowfront, the San Francisco Edwardian flat.
The contemporary equivalent is the SB-9 split lot in California and the missing-middle infill housing being legalised across western US cities. Portland, Oregon enacted Residential Infill Project rules in 2021 that allow up to four units on lots as small as 5,000 sq ft, and recent zoning changes in Minneapolis, Berkeley, and Sacramento have all moved in the same direction. A 0.04-acre parcel produced by an SB-9 lot split can host an accessory dwelling unit (ADU) of around 800 to 1,000 finished sq ft, which is a 20 percent reduction in size compared to the 1,200 sq ft California ADU statutory limit but well within typical permit-by-right rules.
For non-residential uses, 0.04 acres is the size of a small commercial pad: a single-bay car wash, a coffee kiosk drive-through (if zoning permits no on-site seating), an ATM and signage island, a self-storage office trailer, or the operations footprint for a small mobile-business franchise like a pop-up coffee cart. A standard 8-foot-wide cell tower compound with security fencing and the equipment shelter typically occupies 2,500 to 4,000 sq ft, so 0.04 acres is just below the lower end of the cell-tower footprint.
The most common encounter with the 0.04-acre figure outside city centres is on a partition deed or a remainder parcel after a road taking. State departments of transportation routinely acquire small slivers of frontage land when widening a highway, and the residual parcel left in private ownership is often recorded at 0.02 to 0.05 acres. These are not buildable but generate annual property tax bills, and they show up in tax-sale auctions and quiet-title actions across most US counties.
Sheet 03 · Lot Dimensions Near 0.04 Acres
Standard urban lot sizes that round to 0.04 acres
| City / region | Frontage | Depth | Square feet | Acres |
|---|---|---|---|---|
| New Orleans Creole cottage | 16 ft | 100 ft | 1,600 | 0.0367 |
| Philadelphia trinity | 20 ft | 90 ft | 1,800 | 0.0413 |
| San Francisco micro-lot | 25 ft | 70 ft | 1,750 | 0.0402 |
| Boston bowfront | 18 ft | 95 ft | 1,710 | 0.0392 |
| Baltimore row house | 14 ft | 120 ft | 1,680 | 0.0386 |
| Charleston single house | 32 ft | 55 ft | 1,760 | 0.0404 |
Each of these recorded lot dimensions appears as "0.04 acres" on a tax-assessor record because the rounding is to two decimal places. When a buyer relies on a parcel size for a buildability calculation (lot coverage, floor-area ratio, parking minimums), the recorded plat dimensions are authoritative, not the rounded acreage. A 1,600 sq ft lot and a 1,800 sq ft lot allow noticeably different building envelopes despite both showing 0.04 ac on a public listing.
Adjacent Decimal-Acre Pages
Nearby acreages
Sheet 04 · Common Questions