What an acre looks like
One acre is 43,560 square feet — about a 208.7 ft square, or a football field minus the end zones. Rural listings mix units shamelessly: acres for the parcel, square feet for the building pad. The calculator translates your tape-measure numbers into both, so you can check a listing's claimed acreage against reality.
Irregular lots: split and add
Parcel shapes are rarely rectangles, but almost every shape splits into rectangles and triangles. Measure each piece, calculate separately, and add the totals — five minutes with a tape measure verifies what a survey costs hundreds to tell you.
Sources and standards
Where these figures come from
Every formula on this page is implemented from the published reference material below. Where a value depends on a regional code, the calculator lets you override it rather than assuming one jurisdiction.
- USDA Natural Resources Conservation Service — soil texture, bulk density and seeding rate guidance.
- US Geological Survey — mineral commodity data and aggregate density references.
- National Stone, Sand & Gravel Association — aggregate grading and product specification references.
Figures, formulas and reference tables last verified: 19 September 2026.