How Big Is an Acre? Feet, Dimensions and Comparisons

An acre is 43,560 square feet of land. It is a measure of area with no fixed shape, so an acre can be a square, a long strip or an irregular lot. As a square it is about 208.7 feet on each side. An acre covers about three quarters of an NFL football field with its end zones.

Pillar, a land research software company, wrote this guide. The definitions come from the National Institute of Standards and Technology (NIST), the sports dimensions from each sport's rule book, and the zoning figures from the city codes named. We checked every source on November 15, 2026. The arithmetic is ours and is shown so you can check it. This is general information, so confirm the size of a specific property with a licensed surveyor in your state.

How many square feet are in an acre?

One acre is 43,560 square feet. NIST Handbook 44, Appendix C lists the figure as exact, and lists an acre as 10 square chains and 160 square rods.

The same appendix says an acre has no set shape: "an acre is not necessarily a regular shape, such as a square or rectangle." Any outline that encloses 43,560 square feet is one acre.

How big is an acre in feet? Acre dimensions

An acre has no single length or width. These shapes all hold exactly one acre, or very close to it.

• A square acre. The square root of 43,560 is about 208.71, so a square acre is about 208.71 feet on each side. NIST gives the same figure, 208.710 feet. Walking around it is 4 × 208.71 = about 835 feet.
• The classic acre, 66 by 660 feet. 66 × 660 = 43,560. NIST lists a chain as 66 feet and a furlong as 660 feet, or 10 chains, so this strip is one chain wide and one furlong long.
• 100 feet wide. 43,560 ÷ 100 = 435.6 feet deep.
• 150 feet wide. 43,560 ÷ 150 = 290.4 feet deep.
• 200 feet wide. 43,560 ÷ 200 = 217.8 feet deep.
• 50 feet wide. 43,560 ÷ 50 = 871.2 feet deep.

To size any rectangular acre, divide 43,560 by the width in feet. The answer is the depth.

How long is an acre?

It depends on the width. A square acre is about 208.7 feet long. The traditional acre is 660 feet long and 66 feet wide. An acre only 10 feet wide would run 4,356 feet, which is more than three quarters of a mile.

Why is an acre 43,560 square feet?

The number comes from the old strip of plowland, one furlong by one chain. The University of Nottingham's guide to historical weights and measures says the acre "was defined officially as being 1 furlong (40 poles = 660 feet) in length, and 4 poles (66 feet) in breadth." The same guide gives the traditional meaning of an acre as the area a team of eight oxen could plough in one day, and says "furlong" comes from "a furrow long."

How big is an acre compared to a football field?

An acre is smaller than a football field. The two figures people quote, about 76% and about 91%, differ only in whether the end zones are counted.

The 2026 NFL rule book (Rule 1, Section 1, Article 1) says the game is played on "a rectangular field, 360 feet in length and 160 feet in width," with goal lines 10 yards in from each end line.

• With end zones. 360 × 160 = 57,600 square feet. 57,600 ÷ 43,560 = 1.32 acres. One acre is 43,560 ÷ 57,600 = 75.6% of the field.
• Without end zones. The goal lines sit 30 feet inside each end, so the field of play is 300 × 160 = 48,000 square feet, or 1.10 acres. One acre is 43,560 ÷ 48,000 = 90.75% of it.

To picture it, stand on one goal line. At 160 feet wide, an acre reaches 43,560 ÷ 160 = 272.25 feet up the field. That is 90.75 yards, so the acre ends a little past the 10-yard line at the far end.

These are NFL dimensions. A high school or college field follows its own rule book.

How big is an acre compared to other things?

Each comparison below uses a published dimension.

• A soccer field. A soccer pitch is a range, not one size. The IFAB Laws of the Game (Law 1) set the touchline for international matches at 110 to 120 yards and the goal line at 70 to 80 yards. The smallest is 330 × 210 feet = 69,300 square feet, or 1.59 acres. The largest is 360 × 240 feet = 86,400 square feet, or 1.98 acres. For other matches the Laws allow 100 to 130 yards by 50 to 100 yards, with the touchline longer than the goal line, which runs from 1.03 acres (300 × 150 feet) up to 2.69 acres (390 × 300 feet). We used the yard figures printed in the Laws.
• A tennis court. The ITF's 2026 Rules of Tennis (Rule 1) make the court 78 feet long and, for doubles, 36 feet wide. 78 × 36 = 2,808 square feet, and 43,560 ÷ 2,808 = 15.5 doubles courts per acre. That counts only the area inside the lines, with no space to run behind or beside the court, so fewer real courts fit.
• A downtown Portland block. Portland, Oregon's planning bureau describes the Central City's "200' by 200' block structure" in its 2009 Urban Form report. 200 × 200 = 40,000 square feet, or 0.92 acre. An acre is about 9% larger than one of those blocks. City blocks vary widely. The report itself says Portland "includes a diverse and varied range of urban patterns," so do not treat this as a standard block.

How big is half an acre, 5 acres and other common sizes?

The figures below are our arithmetic: acres × 43,560 for square feet, then the square root for the side of a square. Real parcels are rarely square.

• Quarter acre: 10,890 square feet, about 104.4 feet on each side
• Half acre: 21,780 square feet, about 147.6 feet on each side
• 1 acre: 43,560 square feet, about 208.7 feet on each side
• 2 acres: 87,120 square feet, about 295.2 feet on each side
• 5 acres: 217,800 square feet, about 466.7 feet on each side
• 10 acres: 435,600 square feet, 660 feet on each side
• 20 acres: 871,200 square feet, about 933.4 feet on each side
• 40 acres: 1,742,400 square feet, 1,320 feet (a quarter mile) on each side
• 160 acres: 6,969,600 square feet, 2,640 feet (a half mile) on each side
• 640 acres: 27,878,400 square feet, 5,280 feet (one mile) on each side

The last three are the building blocks of the federal Public Land Survey System. NIST lists a section of land as approximately 1 mile square, and a square mile is 640 acres. A quarter section is nominally 160 acres and a quarter of that is 40. Actual sections vary, so the acreage of a real one comes from its survey. Our guide to township and range descriptions shows how to read them.

Five acres is also 5 × 43,560 ÷ 57,600 = about 3.8 NFL fields with end zones.

How big is a hectare vs. an acre?

A hectare is about two and a half times the size of an acre. NIST lists one hectare as 10,000 square meters, or 2.471 acres, and one acre as exactly 0.40468564224 hectare.

The other conversions, from the same NIST appendix or simple arithmetic on it:

• Square feet: 43,560
• Square yards: 4,840 (43,560 ÷ 9, since a square yard is 9 square feet)
• Square meters: 4,046.8564224
• Hectares: about 0.4047
• Square miles: 0.0015625, which is 1/640

One footnote on old records. Until the end of 2022 the acre was defined with the US survey foot, which is slightly longer than the international foot. NIST and NOAA's National Geodetic Survey deprecated it. NIST's notice reads: "Beginning on January 1, 2023, the U.S. survey foot should be avoided, except for historic and legacy applications." For acreage the change is tiny. The agencies' Federal Register notice says "the difference in area for 1 acre is only 0.000 004 acre," which it puts at about 25 square inches.

How many houses fit on an acre?

There is no national answer, because each city or county sets its own minimum lot size. Here is the arithmetic for two cities' codes. Divide 43,560 by the minimum lot area and round down.

• Raleigh, North Carolina. The detached house standards in the Unified Development Ordinance (Sec. 2.2.1, conventional development option) set a minimum lot of 10,000 square feet in R-4 and 4,000 square feet in R-10. 43,560 ÷ 10,000 = 4.36, so four lots. 43,560 ÷ 4,000 = 10.89, so ten lots. In R-1 the minimum is 40,000 square feet and density is also capped at 1 unit per acre, so one house.
• San Diego, California. The RS zones allow one dwelling unit per lot. The minimum lot is 5,000 square feet in RS-1-7 and 40,000 square feet in RS-1-1. 43,560 ÷ 5,000 = 8.71, so eight lots. 43,560 ÷ 40,000 = 1.09, so one lot.

Those counts are ceilings from lot area alone. They assume every square foot of the acre becomes a lot. In a real subdivision, land also goes to streets, and lots must meet minimum widths, setbacks and often a limit on impervious surface or space for stormwater. Other rules can change the count in either direction, including state laws on duplexes and accessory units, which our R1 zoning guide covers. Read the code that applies to the site before you count lots.

What an acre means when you are buying land

The unit is fixed. The acreage printed for a particular property is not, and it can come from several places.

Gross acres and net acres. Local codes often count land two ways. American Canyon, California, is one example. Its code defines a gross acre as the area of a lot or site "including easements of right-of-way to be dedicated, but excluding existing public rights-of-way," and a net acre as the area "remaining after dedication of all required rights-of-way." Each jurisdiction writes its own definition. Find out which acreage a density limit uses. At the same density, subtracting land for required rights-of-way can reduce the number of lots allowed.

Three numbers for one property. The deed may state an acreage. The county assessor's record may show another. The county's GIS map can compute a third from the parcel outline. West Virginia's guide to deeded and calculated acreage says that because its tax map parcels are not mapped to surveyor scale, calculated acreage "should only be used as a reference or estimate." Sacramento County says its assessor parcel maps are prepared for assessment purposes only and are not surveys. Those are two examples, and other states and counties set their own practice. Our guide to deeded acres vs. GIS acres explains where each figure comes from and how to compare them.

Where the acreage shows up. Look in the deed's legal description, the assessor's parcel record, the recorded plat if the land was subdivided, the listing, and any survey. Write down which document each number came from.

How to check it yourself. You can outline the parcel on aerial imagery with our free acreage calculator, which reports acres and square feet and compares the result with the deeded and GIS figures. That is a screening estimate. It does not locate a boundary.

When a survey decides it. The West Virginia guide says a survey can usually determine the precise acreage of a parcel, and that if exact acreage is material to a purchase, the owner likely needs a current one. A boundary survey is the document to order when price, lot yield or a property line depends on the number.

Before you make an offer, check these:

1. Which acreage the price is based on, and which document it came from.
2. Whether the deed, the assessor and the GIS map agree, and by how much they differ.
3. Whether the local code counts density on gross or net acres.
4. How much of the land is taken by easements, rights-of-way, floodplain or wetlands. Acreage says nothing about how much is usable.
5. Whether the contract should be conditioned on a survey when the price is set per acre. Ask a real estate attorney in your state how to write that.

Pillar's property search shows a parcel's recorded acreage alongside ownership, zoning and land use, which is a starting figure to check against the documents above.

Quick answers

How big is an acre of land? 43,560 square feet. As a square, about 208.7 feet on each side.

How many feet is an acre? An acre is an area, so it is measured in square feet: 43,560. As lengths, a square acre is about 208.7 by 208.7 feet, and the traditional acre is 66 by 660 feet.

Is an acre bigger than a football field? No. An NFL field with end zones is 57,600 square feet, or 1.32 acres. An acre is 75.6% of that, and 90.75% of the 48,000 square feet between the goal lines.

How big is half an acre? 21,780 square feet, about 147.6 feet on each side as a square.

How big is 5 acres? 217,800 square feet, about 466.7 feet on each side as a square, or about 3.8 NFL fields with end zones.

How many acres are in a square mile? 640. A square mile is 27,878,400 square feet.

Which is bigger, an acre or a hectare? A hectare. One hectare is about 2.471 acres, and one acre is about 0.4047 hectare.