Acreage Calculator

Convert any plot of land to acres in seconds. Choose your shape, enter the dimensions in feet or meters, and you'll see square feet, acres, hectares, and square meters side by side. Built for builders, land buyers, and anyone trying to picture how much "0.7 acres" really is.

Common Acreage Comparisons

How to Calculate Acreage

For rectangular lots, the math is simple: length × width = area in square feet, then divide by 43,560 to get acres. For circles, use π × r². For triangles, ½ × base × height. Irregular lots can be split into rectangles and triangles, summed, and divided by 43,560.

If you only have a deed area in square feet, divide by 43,560 directly. If you have meters, convert: 1 acre = 4,046.86 m². The "Irregular" option in the calculator above accepts a total square footage number directly.

How This Calculator Works

This tool turns field or deed dimensions into a true acre figure. The constant that drives everything is fixed by U.S. survey law: one acre equals exactly 43,560 square feet. So the whole job is computing square footage first, then dividing by 43,560.

How the square footage is found depends on the shape you pick. A rectangle is length × width. A circle uses π × radius², and because you enter the diameter, the tool halves it first. A triangle is ½ × base × height — handy for the wedge-shaped corner lots I survey constantly. If you choose meters, every dimension is multiplied by 3.28084 to convert to feet before the area is taken. The Irregular option skips geometry entirely and divides whatever total square footage you type by 43,560, which is how I handle odd parcels: break them into rectangles and triangles on paper, add the pieces, and enter the sum.

A Worked Example

Say you are pricing a building lot that the plat lists as 150 ft of road frontage and 290 ft deep. Leave the shape on Rectangle and units on Feet, enter 150 and 290. The tool multiplies them: 150 × 290 = 43,500 square feet. Divide by 43,560 and you get 0.9986 acres — essentially a full acre. It also reports 4,041.7 m² and 0.4042 hectares. That tells a buyer the “almost one acre” in the listing is honest, not marketing rounding.

Estimator's tip: Before you trust any acreage number on a listing, ask which line it was measured to. I have walked parcels where the mowed “yard” looked like an acre but the deed acre ran 30 feet into the woods past the fence. Pace the boundaries against the survey pins, and when a lot is described in chains or rods on an old deed, convert carefully — a single rod is 16.5 feet, and the errors compound fast on a long frontage.

What Affects Your Acreage

• Which boundary you measure to — survey pins, fence line, or road centerline can differ by several feet.
• Slope: deeds record flat (plan-view) area, so a steep hillside has more walking surface than its recorded acreage.
• Right-of-way and easements that legally count in the parcel but you cannot build on.
• Rounding in the original plat — older deeds were often measured in chains and rods.
• Irregular boundaries that you have to split into shapes; missing a triangle throws the total off.

Frequently Asked Questions

How many square feet are in an acre?

Exactly 43,560 square feet. That number is set by definition (a chain of 66 feet by a furlong of 660 feet), so it never changes regardless of the lot's shape.

How big is half an acre?

Half an acre is 21,780 square feet. As a square that is about 147.6 feet on each side; as a typical suburban lot it might read 100 ft wide by 218 ft deep.

Can I calculate acreage for an oddly shaped lot?

Yes. Split the parcel into rectangles and triangles, find each area, add them up, then choose the Irregular option and enter the total square footage. The tool divides by 43,560 for you.

Does acreage account for slope or just flat area?

It uses flat plan-view area, the same basis deeds and surveys use. A sloped acre has more actual ground surface but is still recorded as one acre.