How Many Lots Does This Acreage Actually Yield?
A parcel is advertised in acres, but the zoning ordinance that governs what can be built on it is written almost entirely in square feet: minimum lot area, minimum lot width times depth, maximum lot coverage, floor area ratio, required open space. Nothing in that code can be tested against a parcel until the acreage becomes square feet — which is the first calculation on any feasibility sketch.
What the Square-Foot Figure Unlocks
Minimum lot area by district
Lot coverage and floor area ratio
Land lost to rights-of-way
Density expressed as units per acre
Sketching a Yield Test on a Parcel
Feasibility work runs in one direction: gross acres to gross square feet, deduct the street network, then divide by the code minimum.
Enter the gross parcel acreage
Type the acreage from the listing or the plat — 0.68, 3.5, 12.4 — and the square-foot figure appears immediately. Decimal acres to two or three places are normal here, and a comma decimal mark is accepted.
Take out the right-of-way before dividing
Multiply the gross square feet by roughly 0.70 to 0.75 to reach net developable land. On 152,460 ft², a 25 per cent deduction leaves 114,345 ft², which is 15 lots at a 7,500 ft² minimum rather than the 20 the raw figure suggested.
Carry the number into the yield sheet
The copy button hands over the bare figure with no unit or spacing, so it drops into a pro forma cell or a CAD annotation cleanly. Ctrl + C inside a field does the same thing.
Read a lot area back as an acre fraction
When the plat labels a lot in square feet and the application asks for acres, press the swap button (↔) to reverse the direction — a 9,148 ft² lot comes back as 0.21 acre.
Lot Yield per Acre by Minimum Lot Size
What one gross acre produces at each common minimum lot area, first as raw arithmetic and then after 25 per cent of the land is dedicated to streets and utilities. The gross column is simply 43,560 divided by the lot size; the net column divides 32,670 instead.
| Minimum lot size | Lot area (ft²) | Gross lots per acre | Net lots after 25% right-of-way |
|---|---|---|---|
| Compact single-family | 5,000 ft² | 8.71 | 6.53 |
| Small-lot suburban | 6,000 ft² | 7.26 | 5.45 |
| Standard suburban | 7,500 ft² | 5.81 | 4.36 |
| Quarter-acre lot | 10,890 ft² | 4.00 | 3.00 |
| Large suburban | 12,000 ft² | 3.63 | 2.72 |
| Septic-served lot | 20,000 ft² | 2.18 | 1.63 |
| One-acre minimum | 43,560 ft² | 1.00 | 0.75 |
The gap between the two right-hand columns is the whole argument in most rezoning hearings. At a 7,500 ft² minimum an acre looks like 5.8 lots and delivers about 4.4 once the street network is in, so a 10-acre assembly is realistically 43 lots rather than 58 — and each lot then faces its own coverage and setback limits.
Running the Numbers on a Feasibility Sketch
Test several parcel sizes in a row
Both boxes stay editable, so an assembly of 1.2, 2.6 and 4.1 acres can be run one after another and the square-foot totals added by hand.
Go from platted lot back to acreage
Reversing the direction answers the other half of the job: what fraction of an acre a 9,148 ft² or 12,000 ft² lot represents on an application form.
Metric plans and survey units
The searchable dropdowns cover square metres, square yards and the rood as well, useful when an engineering drawing or an older deed arrives in something other than feet.
Figures a pro forma will take
Values are shown with thousands separated for reading, while the copy button gives the unformatted number a spreadsheet or CAD field expects.
Lot Yield and Zoning Questions
How many 7,500 ft² lots really fit on one acre?
Arithmetically 5.81, since 43,560 divided by 7,500 is 5.808. In a real subdivision, expect around 4.4 after a quarter of the land goes to streets, sidewalks and utility easements, and fewer still if the geometry forces odd corner lots or a cul-de-sac bulb. Only a parcel large enough to share its street frontage across many lots gets close to the theoretical number.
What is the difference between a gross acre and a buildable acre?
A gross acre is the full 43,560 ft² inside the property boundary. A buildable or net acre is what remains after streets and any land the ordinance excludes — floodplain, wetland, steep slope, required open space, existing easements. A parcel with 30 per cent constrained land yields only 30,492 ft² of buildable area per gross acre, so the density the code allows and the density the site delivers are different numbers.
My district allows 4 units per acre — what lot size is that?
Divide 43,560 by 4: one unit per 10,890 ft² of land. If that density is measured on gross acreage, the lots themselves must be smaller than 10,890 ft² to leave room for the street — typically 7,500 to 8,500 ft² each. If it is measured on net acreage, 10,890 ft² is the actual minimum lot area and the streets come out of the parcel before the division.
Does lot coverage or floor area ratio limit a building more?
It depends on the storeys. Coverage limits the ground footprint: 35 per cent of a 10,890 ft² lot is 3,811 ft². An FAR of 0.5 on the same lot allows 5,445 ft² of floor area in total. A single-storey house is stopped by coverage first; a two-storey house is stopped by FAR first. Both apply at once, so the smaller result wins.
Why does a plat show 0.17 acre where the sale sheet says 7,405 square feet?
They are the same lot, rounded differently: 7,405 divided by 43,560 is 0.17001. Two decimal places of an acre is a coarse unit for small lots — one hundredth of an acre is 435.6 ft², enough to swing a lot in or out of compliance with a 7,500 ft² minimum. Test the minimum-lot-area rule against the square-foot figure, and keep the acre figure for the site summary.
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