Quick Answer
To find acres, work out the area in square feet and divide by 43,560. A plot 660 ft long and 330 ft wide is 217,800 sq ft, which is 5 acres. In metric, divide square meters by 4,046.86 to get acres, or by 10,000 to get hectares.
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Table of Contents
- Acreage Calculator
- Quick Answer
- Related Calculators
- How This Acreage Calculator Works
- How to Use the Acreage Calculator
- Acreage Formulas
- Key Terms
- Worked Example
- Real-Life Examples
- Acres vs Hectares
- Common Plot Sizes in Acres
- Measuring Land Accurately
- Common Mistakes to Avoid
- Frequently Asked Questions
- References & Sources
How This Acreage Calculator Works
Land in the United States is usually measured and sold in acres. Choose the shape of your land, pick the unit you measured in, and enter the sizes. The calculator works out the area in square feet, then divides by 43,560 to give acres. It also shows square yards, square meters, hectares and square miles, and the value of the land if you add a price per acre.
Quick explanation: one acre is 43,560 square feet.
- A square acre is about 208.7 ft on each side.
- In metric, one acre is about 4,047 square meters, or 0.405 hectares.
- A square mile holds 640 acres.
How to Use the Acreage Calculator
- Choose the land shape, or pick ‘I know the area’.
- Pick the unit you measured in: feet, yards, meters or miles.
- Enter the sizes of the land.
- Optionally, add a price per acre.
- Press Calculate to see acres, square feet, hectares and the value.
Acreage Formulas
- Rectangle: acres = length × width ÷ 43,560 (in feet)
- Triangle: acres = base × height ÷ 2 ÷ 43,560
- Circle: acres = π × (diameter ÷ 2)² ÷ 43,560
- Trapezoid: acres = (side 1 + side 2) ÷ 2 × distance between them ÷ 43,560
- Hectares: square meters ÷ 10,000; acres to hectares: × 0.404686
Key Terms
- Acre: a unit of land area equal to 43,560 square feet, or 1/640 of a square mile.
- Hectare: a metric unit of area equal to 10,000 square meters.
- Square foot: the area of a square 1 ft on each side.
- Plat map: a county map that shows the boundaries and sizes of land parcels.
- Gross and usable acres: the whole parcel versus the part that can actually be used.
Worked Example
A field is shaped like a trapezoid. Its two parallel sides are 300 ft and 500 ft, and they are 200 ft apart.
- Average width = (300 + 500) ÷ 2 = 400 ft
- Area = 400 × 200 = 80,000 sq ft
- Acres = 80,000 ÷ 43,560 = 1.8365 acres
- At $12,000 an acre, the land would be worth about $22,039.
Real-Life Examples
- House lot: a 100 ft by 150 ft lot is 15,000 sq ft, or 0.344 acres, about a third of an acre.
- Football field: the playing field of 360 ft by 160 ft (end zones included) is 1.32 acres.
- Metric plot: 100 m by 100 m is 1 hectare, or 2.471 acres.
- Round pond: a pond 500 ft across covers 4.51 acres.
Acres vs Hectares
- Acre: a US customary and imperial unit of 43,560 square feet, used for land in the US and UK.
- Hectare: a metric unit of 10,000 square meters, used for land in most other countries.
- Converting: 1 hectare is about 2.471 acres, and 1 acre is about 0.4047 hectares.
Common Plot Sizes in Acres
Rounded to three decimals.
| Plot size (feet) | Square feet | Acres |
|---|---|---|
| 50 × 100 | 5,000 | 0.115 |
| 100 × 100 | 10,000 | 0.230 |
| 100 × 200 | 20,000 | 0.459 |
| 208.71 × 208.71 | 43,559.864100000006 | 1.000 |
| 300 × 300 | 90,000 | 2.066 |
| 660 × 330 | 217,800 | 5.000 |
| 660 × 660 | 435,600 | 10.000 |
| 1,320 × 1,320 | 1,742,400 | 40.000 |
Measuring Land Accurately
Measure along the ground with a long tape or a measuring wheel, or use the plat map from the county. If the land slopes, the map area is measured on the flat, so pacing up and down a hill gives a slightly larger number than the legal acreage. For an irregular plot, split it into simple shapes, find the acres of each with this calculator and add them up.
Listings often say “gross acres” (the whole parcel) and “usable acres” (minus roads, wetlands and steep ground). If you plan to build, farm or fence, check which one you are being quoted.
Common Mistakes to Avoid
- Multiplying in mixed units. Use the same unit for every side.
- Dividing by the wrong number. Acres need 43,560, not 4,840 (that is square yards per acre).
- Treating an odd shape as a rectangle. Split it into simple shapes first.
- Using the diameter as the radius. For a circle, halve the diameter before squaring it.
- Relying on a rough measure for a sale. Use the survey or deed for legal acreage.
Frequently Asked Questions
There are 43,560 square feet in one acre.
Multiply length by width in feet to get square feet, then divide by 43,560.
About 208.7 ft by 208.7 ft if it is square, or about 90% of an American football field without the end zones.
One hectare is about 2.471 acres.
A square mile holds 640 acres.
Split it into rectangles and triangles, find the acres of each and add them up.
About 4,046.86 square meters.
There are 4,840 square yards in an acre.
A quarter acre is 10,890 sq ft, about 104 ft by 104 ft, a common suburban lot size.
References & Sources
| Source | Used For | Link |
|---|---|---|
| NIST, Guide to the SI, Appendix B.8: Factors for units listed alphabetically | Conversion factors for the acre and hectare. | https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8 |
| NIST, U.S. survey foot | The US survey foot was retired at the end of 2022; the international foot (0.3048 m) is used. | https://www.nist.gov/pml/us-surveyfoot |