How to use the land subdivision lot yield calculator
- Enter the gross area of the parcel and choose its unit: acres, square feet, hectares or square meters.
- Enter the shares of the area set aside for roads, open space and anything else, such as drainage ponds or easements.
- Enter the smallest lot you plan to sell and its unit.
- Read the number of lots, the net land, the land left over and the table showing where the land goes.
Formula
net land = gross area x (1 - roads % - open space % - other %)
lots = whole number of times the smallest lot fits in the net land
leftover = net land - lots x smallest lot
Lots multiplied by the smallest lot plus the leftover equals the net land. The average lot is the net land divided by the number of lots, if the leftover is shared out. Units are converted with 1 acre = 43,560 square feet.
Twenty acres, quarter-acre lots
A 20-acre parcel with 20% for roads, 10% for open space and 5% for other uses keeps 65% as net land, which is 13 acres or 566,280 square feet. A quarter acre is 10,890 square feet, and 566,280 / 10,890 = 52 exactly.
The result is 52 lots with nothing left over, or 2.60 lots per gross acre. With 2-acre lots instead, 13 acres hold 6 lots (6.5 rounded down) and 1 acre is left over.
A first count, not a design
The percentages do the work here. Roads often take a large share, open space and stormwater facilities more, and the shape of the parcel changes how well lots fit along the roads. A real layout must meet the local rules on lot size, frontage, setbacks and access, which the page does not know. Use it to compare options, such as larger lots against more of them, before asking a surveyor or planner.
To check a single lot, see the Lot Coverage Calculator and the Floor Area Ratio Calculator. To work out the area of a parcel from its sides, use the Square Footage Calculator, and for the cost of owning a home on one of the lots, the Home Ownership Cost Calculator.
Rounding and leftovers
Lots are counted in whole numbers, so a net area just below a multiple of the lot size loses a lot to the rounding. The leftover row shows how close you were. Small changes to the set-aside shares can add or remove a lot, so try a few values.
Assumptions and limits
- The set-asides are shares of the gross area and must total less than 100%.
- Every lot is at least the smallest lot, and none is larger than needed.
- Conversions use 1 sq m = 10.7639 sq ft and 1 hectare = 10,000 sq m.
- No zoning, frontage, slope, wetlands or utilities are considered.
- The percentages and sizes shown are examples, not planning standards.
Frequently asked questions
Why not use the whole parcel for lots?
Land is needed for roads, utilities, drainage and often open space before lots can be cut. The set-aside shares stand for that.
How do I find the right percentage for roads?
Ask the planning authority or a designer, or measure a similar layout. The page cannot know your site.
What is the average lot?
The net land divided by the number of lots. It is larger than the smallest lot when there is leftover land.
Can I mix lot sizes?
Not directly. Run the page once for each size, using the area you plan to give to that size as the gross area.