What Is Acre (ac)?
An acre is a unit used to measure land area. People use it to tell how big a piece of land is, such as a field, farm, or house lot.
It is not a metric unit. It comes from old English measuring systems, but it is still used a lot today in many countries.
One acre is a little smaller than an American football field, including the end zones. You can also imagine it as a square that is about 209 feet on each side.
Definition
An acre is a unit for measuring area on the surface of land.
- Exactly 1 acre = 43,560 square feet
- About 1 acre = 4,047 square meters
- About 1 acre = 0.4047 hectare
- Exactly 1 acre = 4,840 square yards
- Exactly 1 square mile = 640 acres
The official modern acre is based on the international yard, which is fixed in meters. This makes the acre the same size in every country that uses it.
History / Origin
The acre is a very old unit. It started in early medieval England.
Long ago, an acre was not defined with numbers. Instead, it meant the area of land a team of oxen could plow in one day. Because farms and tools were different in each place, the size of an acre was not always the same.
Over time, people wanted clear and equal measures. In England and later in Britain, laws slowly fixed the size of the acre using yards, feet, and rods. Different types of acres existed for a while, such as the Scottish acre and Irish acre, but these were larger than the English acre.
In 1959, several English speaking countries agreed on the exact length of the yard in meters. After that, the international acre became fixed as 4,046.8564224 square meters. This is the value used in science and in most legal uses today.
Symbol & Abbreviation
The main symbol for acre is:
- ac
Sometimes people write the full word acre, and sometimes they mix styles, such as:
- 1 ac
- 1 acre
- Area 5 ac
All these mean the same unit. There is no dot needed after ac in modern use.
Current Use Around the World
The acre is still used in many parts of the world, even though most countries use the metric system for most things.
Widely used:
- United States Land for homes, farms, parks, and maps is often given in acres.
- United Kingdom Still common in property ads and for rural land, even though hectares are official.
- Canada Often used for farm land and real estate in some regions, along with hectares.
- Ireland Used in everyday talk for land, though the hectare is official.
Also used in some metric countries:
- India, Pakistan, Bangladesh Very common for measuring farm land and village land. Often used with local units like bigha.
- A few African and Caribbean countries Use acres for farm plots and property deals.
In science, engineering, and most government statistics, the hectare and square meter are preferred. But in daily life and in real estate, the acre is still very popular.
Example Conversions
Here are some simple example conversions to help you understand the size of an acre.
From acres to square feet
- 1 acre = 43,560 square feet
- 0.5 acre = 43,560 ÷ 2 = 21,780 square feet
- 2 acres = 43,560 × 2 = 87,120 square feet
From acres to square meters
- 1 acre ≈ 4,047 square meters
- 3 acres ≈ 4,047 × 3 ≈ 12,141 square meters
- 0.25 acre ≈ 4,047 × 0.25 ≈ 1,012 square meters
From acres to hectares
- 1 acre ≈ 0.4047 hectare
- 5 acres ≈ 5 × 0.4047 ≈ 2.0235 hectares
- 10 acres ≈ 10 × 0.4047 ≈ 4.047 hectares
From acres to square miles
- 1 square mile = 640 acres
- 1 acre = 1 ÷ 640 square mile ≈ 0.0015625 square mile
- 320 acres = 320 ÷ 640 = 0.5 square mile
From square meters to acres
You can also go backwards. Use this rule:
- 1 acre ≈ 4,047 square meters
- So 1 square meter ≈ 1 ÷ 4,047 acre ≈ 0.000247 acre
- 2,000 square meters ≈ 2,000 × 0.000247 ≈ 0.494 acre
- 10,000 square meters ≈ 10,000 × 0.000247 ≈ 2.47 acres
Related Units
These units are often used together with acres or instead of acres when talking about land area.
- Square foot (ft²) A very small area unit. Used for rooms and houses. 43,560 square feet in 1 acre.
- Square yard (yd²) Larger than a square foot. 4,840 square yards in 1 acre.
- Square meter (m²) Basic metric unit of area. Used almost everywhere in the world. About 4,047 square meters in 1 acre.
- Hectare (ha) Main metric unit for land. 1 hectare = 10,000 square meters. 1 hectare ≈ 2.471 acres.
- Square kilometer (km²) Very large area unit for cities and countries. 1 km² = 100 hectares ≈ 247.1 acres.
- Square mile (mi²) Large imperial area unit for big regions. 1 square mile = 640 acres.
- Are (a) An older metric unit. 1 are = 100 square meters. 1 hectare = 100 ares ≈ 2.471 acres.
FAQs
Q1. How big is an acre in simple terms
An acre is about the size of a square that is 209 feet on each side. In metric, that is about 64 meters on each side.
Q2. Is an acre bigger than a hectare
No. A hectare is bigger. One hectare is about 2.47 acres. So if you have 1 hectare, you have more land than 1 acre.
Q3. Is an acre a metric unit
No. The acre comes from old English and imperial systems. The metric system uses square meters and hectares instead. But the acre is now exactly linked to meters for clear conversions.
Q4. Why do we still use acres if the world uses metric units
Many people are used to acres for land. Farmers, land owners, and real estate agents in some countries have used acres for generations. Changing habits takes time, so acres and hectares are often used side by side.
Q5. How many acres are in a square mile
There are exactly 640 acres in one square mile. This is a common rule used in maps and land surveys in the United States and some other countries.
Q6. Are there different types of acres
Today almost everyone uses the international acre, which is based on the international yard. In older times there were other local acres, such as Scottish and Irish acres, which were larger. In the United States you may see the term United States survey acre in old maps, but the size difference is very small and not important in daily life.
