Realtors are required to list a lot size of property on an MLS listing. Depending on your region, some real estate agents list it by acres and some by square feet. (i.e. A lot size that is listed at 0.22 would be slightly less than 1/4 of an acre or approx. 9583 sq. feet.)

1 acre is defined as 66 x 660 feet

1 acre foot is exactly 43,560 cubic feet

4840 square yards = 1 acre

6272640 square inches = 1 acre