How to measure acreage

How acreage is measured

Acreage is measured by finding the area of a tract in square feet and dividing by 43,560, the number of square feet in one acre. The formula is:

acres = square feet divided by 43,560

The methods below run from rough to exact. Rough methods answer early questions. Only a survey settles a boundary or a price. Our acreage calculator does the arithmetic.

Check the recorded acreage

The recorded acreage on the deed or the tax record is the fastest starting figure. The county tax office lists an acreage for each parcel, and many deeds state one. Neither is a measurement you can rely on for a sale. Tax acreage often carries forward from old records, and old deeds describe land by landmarks that have moved or gone. Treat the figure as a claim to check. See county records first.

Use the county GIS map

A county GIS map lets you trace a parcel and read its area. Many county GIS viewers include a measuring tool that draws a shape and reports square feet or acres. The parcel lines on these maps come from deeds and plats fitted to aerial imagery, so they can differ from the ground. The result is good for comparison and early questions, not for a closing.

Break an irregular shape into simple pieces

An irregular tract can be measured by dividing it into rectangles and triangles, finding each area, and adding them. A rectangle’s area is length times width. A triangle’s area is half the base times the height. Measure each piece from a plat or a scaled map, add the pieces in square feet, then divide by 43,560.

For example, a rectangle 400 feet wide and 1,089 feet deep covers 435,600 square feet. Divided by 43,560, that is 10 acres.

Curved boundaries, such as a stream or a road, add error, because straight pieces only approximate them.

Walk the boundary with a GPS app

A GPS app on a phone measures acreage by recording points as you walk the boundary. The app joins the points and reports the enclosed area. Phone GPS drifts, especially under tree cover, so the result is a rough check. It helps when no good map exists or when you want to see where fences and corners sit.

Order a survey for the exact figure

A survey by a licensed surveyor gives the exact acreage. The surveyor researches the deeds, finds or sets the corner markers, measures the boundary on the ground, and prepares a plat. Lenders, buyers, and courts rely on that plat. A survey also shows encroachments, easements, and access problems that no map reveals. See parcels and boundaries.

Measured acres are not usable acres

The acreage you measure is gross acreage. Floodplain, wetlands, steep slopes, and easements reduce the land you can use. See gross acres vs net acres.

Converting between acres and square feet

To convert acres to square feet, multiply by 43,560. To convert square feet to acres, divide by 43,560. Our acres to square feet tool does it in one step.

Questions

Can I trust the acreage on a tax record?

Use it as a starting figure. Tax acreage often comes from old deeds or estimates, and it can differ from a survey. Only a survey settles it.

How many square feet are in an acre?

One acre is 43,560 square feet. That figure is fixed by definition and does not change with the shape of the land.

Can I measure acreage myself?

Yes, for a rough figure. A county GIS tool, a plat, or a GPS app gives a working estimate. For a sale, a boundary, or a loan, rely on a survey.