Acres to Square Feet Calculator | Sq Ft, Sq Yd, Hectares & Sq Miles

Q: How many square feet are in an acre?

43,560 square feet, exactly. It is a defined value, not a measurement, so there is no rounding and no disagreement between sources. The number is historical: an acre was one surveyor's chain by one furlong, and 66 ft x 660 ft = 43,560 sq ft.

Q: How big is an acre in feet, side to side?

As a perfect square, each side is the square root of 43,560, which is about 208.71 ft. An acre does not have to be square: the same area is 100 ft by 435.6 ft, 66 ft by 660 ft, or 50 ft by 871.2 ft.

Q: How many square feet is a quarter acre?

10,890 square feet, which is 43,560 divided by 4. As a square that is about 104.36 ft on a side and roughly 417 ft of fence around it. An eighth of an acre is 5,445 sq ft, a third is 14,520 sq ft and a half is 21,780 sq ft.

Q: Is an acre the same as a football field?

Not quite. An American football field is 100 yd by 53 1/3 yd between the goal lines, which is 48,000 sq ft, so an acre of 43,560 sq ft is about 91 percent of the playing area. Including both 10 yd end zones the field is 120 yd by 53 1/3 yd, or 57,600 sq ft, which is 1.32 acres.

Q: How do I convert acres to hectares?

Multiply acres by 0.404686, or divide by 2.4710538. One hectare is 10,000 square meters by definition, which is 107,639.104 sq ft or 2.4710538 acres. Those acre figures are rounded because the conversion is not a whole number: 1 ft = 0.3048 m exactly, so 1 sq ft = 0.09290304 sq m exactly.

Q: How many acres are in a square mile?

640 acres, exactly. A square mile is 5,280 ft on a side, or 27,878,400 sq ft, and 27,878,400 divided by 43,560 is 640. In the Public Land Survey System one square mile is a section of 640 acres, a quarter section is 160 acres, and a quarter of that is 40 acres.

Q: Why does my deed or tax record disagree with this calculator?

Usually the boundary, not the conversion. Recorded acreage comes from a survey of a parcel with curves and angles and is often rounded on the record, so multiplying it by 43,560 will not reproduce a surveyed square footage. Gross acreage including easements also differs from net usable acreage, and parcels described before 2023 may use the US survey foot, retired at the end of 2022, which differs from the international foot by 2 parts per million.

Q: How do I work out the acreage of my own lot?

Multiply frontage by depth to get square feet, then divide by 43,560. A 75 ft by 150 ft lot is 11,250 sq ft, or 0.258 acres. For an irregular lot, break it into rectangles and triangles, add them up, then convert. For anything legal or financial, use the recorded plat or a licensed survey.

Jump to a common lot size

Area ConverterTWO WAY

Type in any box. The other five update as you type. Nothing reloads.

Acres

Square feet

sq ft

Square yards

sq yd

Square meters

sq m

Hectares

Square miles

sq mi

Reading your entry.

What That Looks Like1:SCALE

Solid blue is the same area as a square. Dashed orange is the same area as a rectangle at the width you set below. Both are drawn to the same scale.

ResultLIVE

1 acre in square feet

43,560.00 sq ft

1 ac | 4,840 sq yd | 4,046.86 sq m | 0.404686 ha | 0.0015625 sq mi

Square plot, side208.71 ft

Square plot, perimeter834.84 ft

Rectangle at your width100 x 435.60 ft

Acres

Square feet

43,560

Hectares

0.404686

Rectangle width (the road frontage, or the side you already know)

ft in

The feet box takes tape-measure shorthand as well as decimals. Try 100, 100ft 6in, 100' 6", 100 6 or 66 1/2. Whatever you type gets echoed back so you can see how it was read.

How This Is CalculatedSHOW THE WORKING

Enter an area and the full working appears here.

Everything on this page runs through one canonical figure in square feet, so no two boxes can drift apart. These are the constants used, and where a value is exact it is marked exact:

1 acre = 43,560 sq ft, exact. It comes from the old surveyor's chain: one chain (66 ft) by one furlong (660 ft) is 43,560 sq ft.
1 sq yd = 9 sq ft, exact, because a yard is 3 ft and 3 x 3 = 9.
1 sq mile = 640 acres = 27,878,400 sq ft, exact. That is one section of the Public Land Survey System.
1 ft = 0.3048 m, exact by international agreement since 1959, so 1 sq ft = 0.09290304 sq m exactly and 1 sq m = 10.7639104167 sq ft.
1 hectare = 10,000 sq m, exact by definition. That works out to 107,639.104 sq ft and 2.4710538 acres, both rounded.

A note on the survey foot. Until 2022 the United States also used a slightly different US survey foot for land surveying, longer than the international foot by 2 parts per million. It was retired for new work at the end of 2022. The difference is about 0.09 sq ft on a full acre, so it changes nothing for a homeowner, but it can matter on a legal description of a large parcel. If a deed figure and this page disagree by a hair, that is usually why.

Conversion Ticket#ACRE

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Handy for a listing sheet, a fencing quote or a call to the county assessor.

Lot Size Quick Reference

Common lot sizes, and the square plot they make
Lot size	Square feet	Square yards	Square meters	Square plot	Fence around it
1/8 acre	5,445	605	505.86	73.79 x 73.79 ft	295.16 ft
1/4 acre	10,890	1,210	1,011.71	104.36 x 104.36 ft	417.42 ft
1/3 acre	14,520	1,613.33	1,348.95	120.50 x 120.50 ft	482.00 ft
1/2 acre	21,780	2,420	2,023.43	147.58 x 147.58 ft	590.32 ft
1 acre	43,560	4,840	4,046.86	208.71 x 208.71 ft	834.84 ft

Square plot dimensions are the square root of the area, rounded to two decimal places. Real lots are almost never square, so treat this as the shape of the area, not the shape of your parcel. Use the rectangle width box above for your actual frontage.

One unit of each, in every other unit
1 of this	Acres	Sq ft	Sq yd	Sq m	Hectares
Acre	1	43,560	4,840	4,046.86	0.404686
Square foot	0.00002296	1	0.1111	0.09290304	0.0000092903
Square yard	0.00020661	9	1	0.83612736	0.0000836127
Square meter	0.00024711	10.7639	1.19599	1	0.0001
Hectare	2.4710538	107,639.10	11,959.90	10,000	1
Square mile	640	27,878,400	3,097,600	2,589,988.11	258.9988

Acres, and how wide a lot has to be to fit
Area	Sq ft	At 50 ft wide	At 66 ft wide	At 100 ft wide
1/8 acre	5,445	108.90 ft	82.50 ft	54.45 ft
1/4 acre	10,890	217.80 ft	165.00 ft	108.90 ft
1/3 acre	14,520	290.40 ft	220.00 ft	145.20 ft
1/2 acre	21,780	435.60 ft	330.00 ft	217.80 ft
1 acre	43,560	871.20 ft	660.00 ft	435.60 ft
5 acres	217,800	4,356.00 ft	3,300.00 ft	2,178.00 ft

The 66 ft column is there because 66 ft is one surveyor's chain, and an acre is exactly one chain by one furlong, so the depth lands on a clean 660 ft.

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Acres to Square Feet FAQ

How many square feet are in an acre?

43,560 square feet, exactly. This is a defined value, not a measurement, so there is no rounding and no disagreement between sources. Every honest calculator returns the same number.

It looks arbitrary because it is historical. An acre was the area of one chain by one furlong, the strip a team of oxen could plow in a day. A surveyor's chain is 66 ft and a furlong is 660 ft, and 66 x 660 = 43,560. The number has been carried forward unchanged ever since.

How big is an acre in feet, side to side?

If you make it a perfect square, each side is the square root of 43,560, which is about 208.71 ft. Squared back up, 208.71 x 208.71 = 43,559.86 sq ft, so 208.71 is a rounded figure and the exact side is an irrational number.

An acre is not required to be square, though. The same area is 100 ft x 435.6 ft, or 66 ft x 660 ft, or 50 ft x 871.2 ft. Set your real frontage in the rectangle width box above and the calculator gives you the depth that goes with it.

How many square feet is a quarter acre?

10,890 square feet. That is 43,560 divided by 4. As a square it is about 104.36 ft on a side, and the fence around that square would be roughly 417 ft.

The other common fractions: an eighth of an acre is 5,445 sq ft, a third is 14,520 sq ft, and a half is 21,780 sq ft. A quarter acre is the classic American suburban lot, which is why so many searches land on it.

Is an acre the same as a football field?

Close, but not the same, and which answer you get depends on whether you count the end zones. An American football field is 100 yd long between the goal lines and 53 1/3 yd wide, which is 48,000 sq ft. An acre is 43,560 sq ft, so an acre is about 91% of the playing area.

Count the two 10 yd end zones and the field becomes 120 yd x 53 1/3 yd, or 57,600 sq ft, which is 1.32 acres. So the whole marked field is a bit over an acre and a quarter, while the part between the goal lines is a bit under an acre. Both figures come straight from the field dimensions in the rulebook.

How do I convert acres to hectares?

Multiply acres by 0.404686, or divide by 2.4710538. One hectare is 10,000 square meters by definition, which works out to 107,639.104 sq ft, or 2.4710538 acres.

Both of those acre figures are rounded, because the conversion is not a whole number. The exact chain runs through the foot: 1 ft = 0.3048 m exactly, so 1 sq ft = 0.09290304 sq m exactly, and everything else follows from that plus the 43,560 sq ft definition of the acre. This page does the arithmetic in that order rather than chaining rounded constants together, which is where small discrepancies usually creep in.

How many acres are in a square mile?

640 acres, exactly. A square mile is 5,280 ft on a side, which is 27,878,400 sq ft, and 27,878,400 divided by 43,560 is exactly 640.

That is not a coincidence. The Public Land Survey System divides the western United States into townships of 36 square miles, each square mile being one section of 640 acres. A quarter section is 160 acres, which was the standard homestead claim, and a quarter of that is the 40 acres in the phrase "the back forty".

Why does my deed or tax record disagree with this calculator?

Usually it is not the conversion, it is the boundary. A recorded acreage comes from a survey of a parcel that has curves, angles and monuments, and it can also be rounded to two decimal places on the record. Multiplying a rounded acreage by 43,560 will not exactly reproduce a surveyed square footage.

Two other honest reasons. Some jurisdictions record gross acreage including a road easement while the assessor lists net usable acreage, and those differ. And parcels described before 2023 may have used the US survey foot, which was retired for new work at the end of 2022 and differs from the international foot by 2 parts per million. On a one-acre parcel that is about 0.09 sq ft, invisible in practice, but it is a real difference on a large tract.

How do I work out the acreage of my own lot?

Measure it as a shape first, then convert. If the lot is a rectangle, multiply frontage by depth to get square feet and divide by 43,560. A 75 ft x 150 ft lot is 11,250 sq ft, which is 0.258 acres.

If it is not a rectangle, break it into rectangles and triangles with the square footage calculator, add them up, then bring the total back here. For anything that will end up in a contract, a permit application or a fence dispute, use the plat or a licensed survey rather than a tape measure and a website.