About

Land area miscalculation is the root cause of boundary disputes, incorrect property valuations, and flawed agricultural yield estimates. The relationship between acres and square feet is fixed at 1 acre = 43,560 ft², a constant derived from the original definition of an acre as 1 furlong × 1 chain (660 ft × 66 ft). This converter applies that exact factor bidirectionally with no rounding until display. Pro Tip: survey acres and international acres differ by approximately 2 parts per million. This tool uses the international acre. For U.S. survey work governed by pre-2023 State Plane Coordinates, consult your local geodetic datum.

Formulas

The conversion uses the internationally defined constant relating acres to square feet:

A_ft² = A_ac × 43,560

For the reverse direction:

A_ac = A_ft²43,560

Where A_ft² is the area in square feet, A_ac is the area in acres, and 43,560 is the exact number of square feet in one international acre. This factor originates from: 1 ac = 66 ft × 660 ft = 43,560 ft².

Reference Data

Acres (ac)	Square Feet (ft²)	Equivalent Context
0.01	435.6	Small urban garden plot
0.05	2,178	Typical single-family lot (dense urban)
0.10	4,356	Standard suburban building lot
0.25	10,890	Quarter-acre residential lot
0.50	21,780	Half-acre suburban estate
1	43,560	Slightly smaller than an American football field
2	87,120	Large estate or small hobby farm
5	217,800	Small agricultural parcel
10	435,600	Approximately 10 football fields
40	1,742,400	Quarter section (PLSS land survey unit)
100	4,356,000	Medium farm or ranch
160	6,969,600	Quarter section (Homestead Act parcel)
320	13,939,200	Half section
500	21,780,000	Large commercial farm
640	27,878,400	One square mile (full section)
1,000	43,560,000	Large ranch or timberland holding

Frequently Asked Questions

The acre descends from medieval English land measurement. It equals 1 chain (66 ft) × 1 furlong (660 ft). The product 66 × 660 = 43,560 is exact, not an approximation. The chain and furlong predate the metric system, so their foot-equivalents produce this non-round constant.

Yes. The U.S. survey foot is defined as exactly 1200/3937 meters, while the international foot is exactly 0.3048 meters. This makes the U.S. survey acre approximately 43,560.174 square international feet - a difference of about 2 parts per million. For parcels under 1,000 acres, the discrepancy is negligible. The U.S. officially deprecated the survey foot on January 1, 2023 (except in some State Plane Coordinate systems).

JavaScript uses IEEE 754 double-precision floating-point arithmetic, which provides approximately 15-17 significant decimal digits of precision. For land areas up to billions of square feet or millions of acres, the results remain accurate well beyond any practical surveying requirement. The converter displays up to 6 decimal places and uses locale-formatted number grouping for readability.

A regulation NFL football field (excluding end zones) is 300 ft × 160 ft = 48,000 sq ft, which equals approximately 1.1023 acres. Including both 30-ft end zones, the total playing surface is 360 ft × 160 ft = 57,600 sq ft ≈ 1.3223 acres.

Yes. Enter any decimal value. For example, a deed listing 0.37 acres converts to exactly 16,117.2 square feet. If your deed states a fraction like 3/8 acre, convert it to a decimal first (0.375) and enter that value. The tool preserves full floating-point precision.

One acre equals exactly 4,046.8564224 square meters, or approximately 0.404686 hectares. Conversely, 1 hectare ≈ 2.47105 acres. This tool focuses on the acres-to-square-feet conversion, which stays within the imperial/U.S. customary system and uses the exact integer factor of 43,560.