How Big Is an Acre? The 43,560 Square-Foot Answer
An acre is 43,560 square feet, or about 90 percent of an American football field. It equals 4,046.86 square metres or 0.4047 hectares. A square acre is 208.71 feet on a side.
Updated April 2026
The Shape of an Acre
An acre is a unit of area, not a fixed shape. It can be any configuration - a square, a narrow rectangle, an L-shape, or an irregular polygon. The only requirement is that the total area equals 43,560 square feet.
Square acre
208.71 ft x 208.71 ft
43,560 sq ft
Classic chain shape
66 ft x 660 ft
43,560 sq ft
Narrow strip
10 ft x 4,356 ft
43,560 sq ft
Why 43,560? The Chain and Furlong
The number 43,560 is not arbitrary. It is the product of two very old units of length that predate the metric system by centuries.
The Gunter's chain (1620)
Edmund Gunter, a 17th-century English mathematician, designed a practical surveying chain of exactly 66 feet, divided into 100 links (each link = 7.92 inches). Ten square chains = one acre. The chain length of 66 feet was chosen because it divides evenly into the mile (80 chains = 1 mile) and the furlong.
The furlong (old English, "furrow long")
A furlong is 660 feet - the traditional distance a team of oxen could plow a furrow without needing to rest. This unit was established in English common law and used across Europe. It is 1/8 of a mile (8 furlongs = 1 mile), and 220 yards.
66 ft x 660 ft = 43,560 sq ft
1 chain x 1 furlong = 1 acre
The 1959 International Yard and Pound Agreement standardised the international foot at exactly 0.3048 metres, which fixed the international acre at exactly 4,046.8564224 square metres. The US survey foot (used before October 2022 for federal land surveys) was slightly longer, giving a marginally different acre value. See acre types and the 2022 NGS deprecation for details.
Real-World Size Comparisons
| Landmark | Acres |
|---|---|
| Singles tennis court | 0.061 |
| NBA basketball court (full arena) | 0.108 |
| US football field - field of play only | 1.1 |
| US football field - incl. end zones | 1.32 |
| Walmart Supercenter (avg footprint) | 4.7 |
| Disneyland Park, California | 85 |
| Vatican City total area | 109 |
| One Manhattan city block (avg) | 5.2 |
| Central Park, New York City | 843 |
How to Measure an Acre Yourself
Google Maps Measure tool
Right-click any location on Google Maps and select 'Measure distance.' Click around your boundary to create a polygon. Google will display the area. Divide square feet by 43,560. Good for rough estimates; not a legal survey.
Walking pace calculation
A square acre is 208.71 feet on a side. If your average walking pace is 2.5 feet, you need roughly 83 paces per side to cross one acre. The perimeter of a square acre is about 835 feet (roughly 334 paces at 2.5 feet per pace).
Handheld GPS or laser rangefinder
Consumer GPS devices and laser rangefinders (Leica Disto, Bosch GLM series) allow you to measure field edges accurately. Most agriculture GPS apps can calculate enclosed area from a walked perimeter.
Licensed land surveyor
For legal descriptions, deeds, subdivision plats, or mortgage-related measurements, hire a licensed surveyor. Only a licensed surveyor can produce a legal description. Do not rely on Google Maps or GPS for property disputes.
Where Acres Are Used
The acre remains the standard land-area unit in the United States, United Kingdom, Canada, and Australia for most real estate purposes. Most of continental Europe, South America, and Asia use hectares (1 hectare = 2.471 acres). India uses a mix of acres, hectares, and local units including the bigha and gunta depending on the region and transaction type.
International agricultural statistics (FAO, USDA foreign reports) typically report in hectares. US domestic statistics use acres.Convert between acres and hectares