Acres to Square Feet Calculator

How the acres to square feet conversion works

One acre is exactly 43,560 square feet. Enter an acreage and the calculator multiplies it by 43,560, then shows the same area in square yards and square meters. Nothing is estimated: the factor is a definition, so the only number that can be off is the acreage you start with. Square feet are the everyday unit for US lots, houses and most building work, which is why an acreage from a deed or listing usually needs converting before it is any use on site.

Going the other way is just as simple. Divide square feet by 43,560 to get acres, so a 7,500 ft² city lot is 0.17 acres.

The exact conversion factor

The acre is one chain by one furlong, 66 ft × 660 ft, which is 43,560 ft². That is a whole number by definition, not a rounded figure. NIST's revised unit conversion factors give the same acre as 10 square chains or 160 square rods. Because a foot is exactly 0.3048 m, a square foot is exactly 0.09290304 m², and an acre is exactly 4,046.8564224 m². The calculator uses 43,560 for square feet, divides by 9 for square yards, and uses the full metric factor for square meters.

What an acre actually measures

The acre began as roughly the land a team of oxen could plow in a day, a strip one furlong long and one chain wide. The shape no longer matters. Any parcel of 43,560 ft² is an acre, whether it is a long rectangle, an L-shaped lot or an irregular field. A square acre measures about 208.7 ft on each side. For a picture that sticks, an American football field without the end zones is 300 ft × 160 ft, or 48,000 ft², which makes it about 1.1 acres.

Acres, square feet, and square yards compared

One acre is 43,560 ft², 4,840 yd² and about 4,047 m². A typical suburban lot runs from about 6,000 ft² (0.14 acres) to 10,000 ft² (0.23 acres), and a one-acre lot counts as large in most US housing markets. Square yards show up where work is priced that way: carpet, and asphalt paving and grading on larger jobs, are commonly quoted per square yard, so 4,840 yd² per acre is the number to divide into a quote. Sod is usually sold by the square foot or by the pallet. Outside the US, land and floor areas are almost always given in square meters or hectares, and the square-meter figure here is the one to use when comparing with an overseas listing or specification.

Worked examples

A quarter-acre lot is 10,890 ft², or 1,210 yd². A half acre is 21,780 ft². A full acre is 43,560 ft² (4,840 yd²). Five acres, a common size for a small hobby farm, comes to 217,800 ft². At the other end of the scale, a section of the US land-survey grid is 640 acres, one square mile, which is 27,878,400 ft² (5,280 ft × 5,280 ft). Every one of these is a single multiplication by 43,560, so there is no rounding to build up.

Where this conversion is used in US practice

Listings usually quote larger lots in acres and smaller city lots in square feet, and zoning codes follow the same split: minimum lot sizes in acres for rural districts, square feet for suburban and urban ones. Once you get into the rules that apply to a specific lot, the work is in square feet. Floor-area ratio, lot coverage and impervious-surface limits in stormwater permits are all calculated that way (setbacks are the exception, being distances in feet), and the IRC and IBC state their area thresholds in square feet too. Landscapers, irrigation designers and turf installers convert acreage to square feet before they work out seed, sod or pipe.

Precision and rounding

Because 43,560 is exact, the conversion adds no error. The calculator shows square feet, square yards and square meters to the nearest whole unit, which is finer than any lot survey. The one wrinkle is historical. Until the end of 2022 the US acre was defined in US survey feet, which made it about 4 parts per million larger. NIST deprecated the US survey foot from January 1, 2023, and the acre is now defined in international feet. The difference is about 0.17 ft² per acre, so on a 100-acre farm it is about 17 ft², far below what any survey can resolve. What really sets the accuracy is the acreage itself, so for anything legal, go by the measured survey or recorded plat, not a listing.

Using this alongside other BuildMetricLab tools

Once a lot area is in square feet, it reads straight into area-based tools: a concrete slab, turf quantities, paint coverage or a fence estimate. The Acres to Hectares calculator gives the metric land-area equivalent, and the Square Feet to Square Meters calculator handles smaller areas for engineering or international work. Every BuildMetricLab tool runs in your browser, with no sign-up and no data sent anywhere, and shows its formula so the math can be audited.