How to Use the Acres Calculator
- Choose the shape of the land: rectangle, triangle or circle.
- Pick the unit you measured in, from feet and meters to miles and chains.
- Enter the length, then the width, or the base and height for a triangle.
- Read the area in acres, with hectares, square feet and square meters below.
In From dimensions mode, choose the shape of the land and the unit you measured in, then type the two measurements. A rectangle needs length and width, a triangle needs a base and its perpendicular height, and a circle needs its radius. Units can be feet, yards, meters, kilometers, miles or surveyor’s chains, which still appear on older Canadian and US land descriptions.
Use Convert an area when you already know the area, for example from a listing in square feet or a European plan in hectares. Both modes show the result in acres with hectares, square feet, square meters, square yards, square miles and square kilometers, plus the side of a square with the same area, which helps you picture the size.
Acreage Formula
An acre is defined as exactly 43,560 square feet. With the international foot fixed at 0.3048 m, that makes one acre exactly 4,046.8564224 square meters.
Triangle: acres = ½ × base × height ÷ 43,560
Circle: acres = π × radius² ÷ 43,560
hectares = acres × 0.40468564224
Worked Example
A rural lot is 660 ft long and 330 ft wide. Its area is 660 × 330 = 217,800 square feet, and 217,800 ÷ 43,560 = exactly 5 acres. In metric that is 20,234.28 m², or 2.0234 hectares. A square with the same area would be 466.69 ft on each side.
In meters, a field of 200 m by 150 m covers 30,000 m², which is 3 hectares or 7.413 acres.
Acres Conversion Table
| Acres | Square feet | Hectares | Square meters | Square side |
|---|---|---|---|---|
| 0.25 | 10,890 | 0.1012 | 1,011.7 | 104.4 ft |
| 0.5 | 21,780 | 0.2023 | 2,023.4 | 147.6 ft |
| 1 | 43,560 | 0.4047 | 4,046.9 | 208.7 ft |
| 2 | 87,120 | 0.8094 | 8,093.7 | 295.2 ft |
| 2.471 | 107,639 | 1 | 10,000 | 328.1 ft |
| 5 | 217,800 | 2.0234 | 20,234.3 | 466.7 ft |
| 10 | 435,600 | 4.0469 | 40,468.6 | 660 ft |
| 40 | 1,742,400 | 16.1874 | 161,874.3 | 1,320 ft |
| 160 | 6,969,600 | 64.7497 | 647,497 | 2,640 ft |
| 640 | 27,878,400 | 258.9988 | 2,589,988 | 1 mile |
Where the Acre Comes From
The acre began as the area a team of oxen could plow in a day, and was later fixed as a strip one furlong (660 ft) long and one chain (66 ft) wide. That is why 10 square chains make an acre, and why a square mile, 640 acres, is the “section” of the Dominion Land Survey in the Canadian Prairies and the Public Land Survey System in the US. A quarter section is 160 acres.
Limits and Accuracy
- Results are as accurate as your measurements. Pacing or estimating from a map can be off by several percent.
- The calculator treats the land as flat. Slopes are measured horizontally on surveys, which is what this tool expects.
- Since January 2023 the US survey foot is retired in favor of the international foot. The difference is 2 parts per million, which only matters for very large surveys.
- For legal boundaries, use the registered survey or deed, not a calculator.
Estimating a Lot from a Map
For a rough figure, many online maps let you measure the distance between two points. Measure the frontage and the depth of the lot, enter them as a rectangle, and the calculator gives the approximate acreage. For a lot shaped like a trapezoid, average the two parallel sides and use that as the length. Remember that map measurements can be off by a few meters, so a small lot may be several percent off. Property assessments, listings and survey plans in Canada usually give the official area in square meters, hectares or acres; use the Convert an area mode to switch between them.
If a lot has a curved road frontage or an irregular back line, the survey plan or the municipal assessment record is the reliable source. Use the calculator to check those figures or to compare lots listed in different units.
Frequently asked questions
How do I calculate acres from feet?
Multiply the length by the width in feet to get square feet, then divide by 43,560. A lot 200 feet by 300 feet is 60,000 square feet, which is about 1.377 acres.
How many square feet are in an acre?
Exactly 43,560 square feet. A square acre is about 208.7 feet on each side, although an acre can be any shape. One acre is also 4,840 square yards or about 4,046.86 square meters.
How many acres are in a hectare?
One hectare is about 2.4711 acres, and one acre is about 0.4047 hectares. A hectare is 10,000 square meters, a square 100 meters on each side, used for land in Canada and most countries.
How do I find the acreage of an irregular lot?
Divide the lot into rectangles and triangles, measure each piece, calculate the acres of each with this tool, and add them together. For curved boundaries, the registered survey plan gives the official area.
How big is an acre compared to a football field?
An American football field without end zones is 300 by 160 feet, which is 48,000 square feet or about 1.1 acres. A Canadian football field is larger, so an acre is noticeably smaller than either.
How many acres are in a square mile?
There are exactly 640 acres in a square mile. That is one section in the Dominion Land Survey used in western Canada and in the US public land survey. A quarter section is 160 acres.