Land could be measured in inches, feet and yards, but the numbers for even a suburban lot would be too large to remember and work with easily. In the United States, land is measured in acres, which are much smaller and easier to work with. An acre is actually an expression of the total area of a land mass.
Obtain the Dimensions

Obtain the deed to the land you want to measure. A standard deed will have information regarding the distance, usually in feet, of the length and width of the parcel. If you do not have the deed you will have to measure the land and usually you will need to hire a surveyor to accurately measure a large or uneven parcel of land.
Area of Rectangle

Calculate the area in feet of the parcel of land. If the lot is rectangular, as are many city lots, multiply the length by the width. If the length of the land is 3,000 feet and the width of the land is 1,800 feet multiply these together to get the total square footage of the parcel, which in this example is 5,400,000 square feet.
Area of Triangle

If the lot is triangular, calculate the area by determining the length of one side, known as the base. Obtain the height by measuring downward from the point to the base. The area of a triangle is base multiplied by height, so if the lot has a base of 500 feet and a height of 200 feet the area is 100,000 square feet.
Area of Parallelogram

If the lot has two parallel sides take the measurement of one of the sides, known as the base and measure the distance from this base to one of the nonparallel sides. If the base is 400 feet and the distance to the nonparallel side is 1,000 feet the area is 400,000 square feet.
IrregularlyShaped Lot

If the lot is irregularly shaped, break down the lot into triangles, rectangles, squares and parallelograms and measure the area separately of each. Add together to get the total square feet.
Convert to Acres

There are 43,560 square feet in one acre. Convert from square feet to acres by dividing the square footage by 43,560. In this example, 5,400,000/43,560 = 124 acres.
If measurements of the parcel are available in yards, calculate the square yardage by multiplying the width and length in yards. If the width of the parcel is 600 yards and the length is 1,000 yards, the area is 600,000 square yards. There are 4,840 square yards in an acre so dividing 600,000/4,840 will give you the number of acres in the parcel. In this example, the parcel is 124 acres.
References
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