There are exactly 43,560 square feet in one acre. That is also 4,840 square yards, or about 4,046.86 square meters. The number looks arbitrary, but it falls straight out of the old English measuring system the acre comes from. This guide explains the origin, gives you a feel for how big an acre really is, and collects the conversions you are most likely to need.
Quick answer
| 1 acre equals | Value |
|---|---|
| Square feet | 43,560 |
| Square yards | 4,840 |
| Square meters | 4,046.8564224 |
| Hectares | 0.40468564224 |
| Square chains (Gunter’s) | 10 |
| Square rods (perches) | 160 |
| Square miles | 1/640 |
To convert square feet to acres, divide by 43,560. To go the other way, multiply by 43,560. The square feet to acres and acres to square feet converters do this for you.
Why 43,560?
The acre predates feet-and-inches arithmetic. It was defined in terms of two older land measures:
- The chain, 66 feet long. In the 1620s the English mathematician Edmund Gunter devised a surveyor’s chain of exactly this length, made of 100 links, which is why it is called Gunter’s chain.
- The furlong, 10 chains or 660 feet. The name comes from “furrow long,” the length of a plowed furrow in a traditional English open field.
An acre is the area of a strip one chain wide and one furlong long:
66 ft × 660 ft = 43,560 sq ft
It is traditionally described as roughly the land a team of oxen could plow in a day, which is why it was long and thin: turning a plow team was slow, so furrows were made as long as practical. The definition never cared about shape, though. Any area of 43,560 square feet is one acre, whether it is a long strip, a square, or an irregular lot.
The chain was so convenient for land work that surveyors kept using it for centuries. Ten square chains make one acre, so a survey measured in chains converted to acres simply by dividing by ten. The rod (16.5 feet, a quarter of a chain) survives in a few places too; see the perch and rood pages for those older units.
What does an acre look like?
Because acres can be any shape, it helps to have a few mental pictures.
- A square acre is about 208.71 feet (63.61 meters) on each side. Pace it out at roughly 70 steps per side if your stride is about 3 feet.
- An American football field, including both end zones, is 360 feet by 160 feet, or 57,600 square feet. That is about 1.32 acres, so an acre is roughly three quarters of a field.
- A soccer pitch of 105 × 68 meters, a common size for international matches, covers 7,140 square meters, or about 1.76 acres. Pitch sizes vary quite a lot, so treat this as a rough guide.
- A typical suburban lot of 50 × 100 feet is 5,000 square feet, about 0.115 acres, so it takes almost nine such lots to fill an acre.
If you would rather see your own land, draw its outline on the map in the land area calculator and read the result in acres.
Acres and hectares
Most of the world measures land in hectares. A hectare is 10,000 square meters, a square 100 meters on each side.
- 1 hectare ≈ 2.4710538 acres
- 1 acre = 0.40468564224 hectares exactly
A quick mental shortcut: a hectare is about two and a half acres. For anything that matters, use the exact factor or the acres to hectares and hectares to acres converters.
Common fractions of an acre
| Acres | Square feet | Square meters | Hectares |
|---|---|---|---|
| 1/4 | 10,890 | 1,011.71 | 0.1012 |
| 1/2 | 21,780 | 2,023.43 | 0.2023 |
| 1 | 43,560 | 4,046.86 | 0.4047 |
| 2 | 87,120 | 8,093.71 | 0.8094 |
| 5 | 217,800 | 20,234.28 | 2.0234 |
| 10 | 435,600 | 40,468.56 | 4.0469 |
Square meter values are rounded to two decimals and hectares to four.
Common lot and parcel sizes
Lot sizes vary widely by region and zoning, but these reference sizes come up often:
| Description | Dimensions or definition | Square feet | Acres |
|---|---|---|---|
| Small urban lot | 50 × 100 ft | 5,000 | 0.115 |
| Mid-size suburban lot | 60 × 120 ft | 7,200 | 0.165 |
| Quarter-acre lot | for example 99 × 110 ft | 10,890 | 0.25 |
| Half-acre lot | for example 132 × 165 ft | 21,780 | 0.5 |
| Quarter-quarter section | 1/16 of a section | 1,742,400 | 40 |
| Quarter section | 1/4 of a section | 6,969,600 | 160 |
| Section | 1 square mile | 27,878,400 | 640 |
The last three come from the US Public Land Survey System, which divides much of the country into townships of 36 sections. See the section and township pages for more.
International acre vs US survey acre
Since 1959 the international foot has been defined as exactly 0.3048 meters, and the acre used in this guide (4,046.8564224 square meters) is based on it.
The United States also kept an older US survey foot, defined as 1200/3937 meters, for land surveying. It is longer than the international foot by about 2 parts per million, which makes the survey acre about 4 parts per million larger: roughly 4,046.8726 square meters, a difference of about 0.016 square meters per acre. That is less than the area of a sheet of letter paper on every acre, far below anything a tape, GPS, or deed would notice.
NIST and the National Geodetic Survey retired the US survey foot for new work on January 1, 2023. Older surveys and state plane coordinates that used it remain valid in their own terms, but for everyday land measurement you can treat the two acres as the same.
Converting in your head
A few rules of thumb that are close enough for a quick check:
- Square feet to acres: divide by 43,560, or roughly by 44,000 for a slightly low estimate.
- Acres to hectares: multiply by 0.4, then add about 1%.
- Hectares to acres: multiply by 2.5, then subtract about 1%.
- Square meters to square feet: multiply by about 10.76.
For exact results, the land area converter handles acres, hectares, square feet, square meters, and many regional units. If you are working out the acreage of an odd-shaped lot first, see how to calculate the acreage of an irregular lot.