What Is the Square Feet to Acres Calculator?
This calculator converts an area measured in square feet (sq ft) into acres. The acre is a unit of land area widely used in the United States and other countries that follow the imperial/US customary system. One acre equals exactly 43,560 square feet, so converting between the two is a simple division.
How to Use It
Enter the area you want to convert in the "Area (square feet)" field and the calculator instantly returns the equivalent number of acres. This is handy for real estate listings, lot sizes, farmland, parks, and construction plans where measurements are recorded in square feet but acreage is the standard reporting unit.
The Formula Explained
The conversion uses the fixed relationship between the two units:
$$\text{acres} = \frac{\text{square feet}}{43{,}560}$$
The figure 43,560 comes from the historical definition of an acre as one chain (66 ft) by one furlong (660 ft), which equals \(66 \times 660 = 43{,}560\) square feet.
Worked Example
Suppose a lot measures 87,120 square feet. Dividing by 43,560 gives \(87{,}120 \div 43{,}560 = 2\) acres. A smaller lot of 21,780 square feet equals \(21{,}780 \div 43{,}560 = 0.5\) acres.
FAQ
How many square feet are in an acre? Exactly 43,560 square feet.
How do I convert acres back to square feet? Multiply the number of acres by 43,560.
Is an acre always the same size? The international/US survey acre used here is 43,560 sq ft. Older land surveys may use the US survey acre, which differs by a negligible amount for everyday use.
