These U.S. area conversions are useful for comparing lots and parcels:
| Area unit | Equivalent |
|---|---|
| 1 acre | 43,560 sq ft = 4,840 sq yd = 4,046.86 sq m = 0.404686 hectare |
| 1 hectare | 10,000 sq m ≈ 2.471 acres |
| 1 square mile | 640 acres = 27,878,400 sq ft |
| 1 sq ft | 0.092903 sq m |
| 1 sq yd | 9 sq ft |
NIST lists an acre as exactly 43,560 square feet and about 4,046.86 square meters. If an acre were a perfect square, each side would be about 208.71 feet; real acres can have other shapes. NIST area conversion tables.
For a rectangular lot, multiply its length by its width to get square feet, then divide by 43,560 to convert square feet to acres.
Example: A 100 × 200-foot rectangle contains 20,000 square feet, or about 0.46 acre. This estimate assumes the lot is a rectangle and uses those measured side lengths. An irregular parcel needs its boundary shape or recorded area; length × width alone may not describe it. For the U.S. public-land section system, see our section of land guide.
A land converter can change an area from acres to square feet or hectares, but it cannot identify where a property line runs. Parcel area and location depend on the physical boundaries and the property's written description. The Bureau of Land Management explains that surveys help make written boundary descriptions accurate and unambiguous. For a specific lot, use its recorded plat or legal description and consult a licensed land surveyor when boundaries must be located. BLM official survey guidance.