Acreage Calculator

An acre is a unit of land area, not of length, so a plot can be long and thin or square and still measure one acre. This land area calculator takes the measurements you have, side lengths in feet, meters, yards, chains or rods, or an area already stated in some unit, and converts it into acres and the other units buyers, sellers and surveyors use.

What Is an Acre?

One acre is 43,560 square feet, which answers the common question about the square footage of an acre. It equals 4,840 square yards, about 4,046.86 square meters, 0.404686 hectare and 1/640 of a square mile. The odd number comes from old English surveying: an acre was a strip one furlong (660 feet) long and one chain (66 feet) wide, roughly what a team of oxen could plow in a day. A square acre is about 208.71 feet on each side.

A hectare, the metric land unit, is 100 × 100 meters, or 10,000 square meters, about 2.471 acres. Most countries record land in hectares or square meters; the United States, the United Kingdom for some purposes, and several other countries still use acres. The calculator uses the international foot of exactly 0.3048 meter. Older US surveys used the slightly longer US survey foot, which differs by about 2 parts per million and was officially retired at the end of 2022; the difference is far below the accuracy of most field measurements.

How to Calculate Acreage

For a rectangular plot, multiply the length by the width in feet and divide by 43,560. The default example is 660 feet by 330 feet: 660 × 330 = 217,800 square feet, and 217,800 ÷ 43,560 = 5 acres exactly. In metric terms that is 20,234.28 square meters, or about 2.0234 hectares. If you know the area in another unit, choose Total Area and pick the unit: 2 hectares, for example, is about 4.9421 acres.

For an irregular four-sided lot, the first extra tool needs all four sides and one diagonal. With sides of 300, 400, 350 and 450 feet and a 500-foot diagonal, the first triangle (300, 400, 500) is a right triangle of 60,000 square feet and the second (350, 450, 500) works out by Heron's formula to about 76,485 square feet, so the lot is about 136,485 square feet, or 3.1333 acres. Four sides alone are not enough, because a four-sided shape can flex like a hinge; the diagonal fixes it.

With corner coordinates, the shoelace formula multiplies each corner's x by the next corner's y, subtracts the reverse product, adds the results around the boundary and halves the total. The default corners (0, 0), (400, 0), (450, 300) and (−20, 280) in feet enclose 126,000 square feet, about 2.8926 acres.

Acres = Length × Width ÷ 43,560 (lengths in feet)

43,560

square feet in one acre (66 ft × 660 ft, a chain by a furlong)

Hectares

acres × 0.404686; one hectare is 10,000 m², about 2.471 acres

Irregular lots: Area = ½ |Σ (xᵢ·yᵢ₊₁ − xᵢ₊₁·yᵢ)| over the corners in order (shoelace formula), or the sum of two Heron triangles split by a diagonal.

Measuring Land with Google Maps and Other Tools

If you do not have a survey, you can estimate boundary lengths from aerial imagery. In Google Maps on a computer, right-click a corner of the property, choose Measure distance and click along the boundary; the Google Maps distance readout shows each length, which you can enter here. Mapping and GIS apps can also give coordinates for each corner. These estimates are useful for planning, fencing or comparing listings, but imagery can be offset by a few feet and does not show legal boundaries.

For a purchase, a building permit, a boundary dispute or a subdivision, rely on the legal description in the deed or a licensed land surveyor. Recorded acreage often differs slightly from what a tape or a map suggests, because surveys account for curved boundaries, easements, road rights-of-way and the method used when the land was first described.

Regional Land Units: Guntha, Cent and Bigha

In India, where land measurement is often called jamin mojani in Gujarati and Marathi, traditional units remain in everyday use alongside acres and hectares. Two of them are fixed fractions of an acre, so the calculator shows them in every result. A guntha is 33 × 33 feet, or 1,089 square feet (121 square yards), and 40 guntha make one acre; it is common in Maharashtra, Gujarat, Karnataka and Telangana. A cent is one-hundredth of an acre, 435.6 square feet, and is widely used in Kerala and Tamil Nadu.

The bigha is deliberately left out, because its size changes from state to state and sometimes between districts. In West Bengal and Assam a bigha is commonly taken as 14,400 square feet, about a third of an acre, while bighas in Rajasthan, Gujarat, Uttar Pradesh and elsewhere can be much larger or smaller. To convert a bigha, check its local size in square feet with the land records office, then enter the plot in square feet.

Frequently asked questions