Hectare (ha) - Unit Information & Conversion

Definition

The hectare (symbol: ha) is a non-SI metric unit of area equal to 10,000 square meters (m²). It is primarily used in the measurement of land. One hectare represents the area of a square with 100-meter sides.

It is equivalent to:

• 1 square hectometer (hm²)
• 100 ares (where 1 are = 100 m²)
• 0.01 square kilometers (km²)
• Approximately 2.471 acres
• Approximately 107,639 square feet (ft²)

The name "hectare" combines the metric prefix hecto- (meaning "hundred") with the unit are.

History

• Origin (French Revolution): The base unit, the are, was defined in 1795 as 100 square meters as part of the new metric system established during the French Revolution. The hectare ("hundred ares") was created alongside it as a larger, more practical unit for land measurement.
• Adoption: While the are saw some use, the hectare quickly became the preferred metric unit for land transactions and agricultural measurements due to its convenient size, bridging the gap between the square meter and the square kilometer.
• International Recognition: The hectare was adopted by the International Committee for Weights and Measures (CIPM) in 1879. Although the are fell out of favor, the hectare gained widespread international acceptance.
• Status with SI: While the official SI unit of area is the square meter (m²), the hectare is explicitly accepted for use with the International System of Units (SI). Its continued use is recognized due to its global importance in land measurement, agriculture, and forestry.

Common Uses

The hectare is the principal metric unit for land area measurement in many fields globally:

• Agriculture: Standard unit worldwide for measuring farm sizes, field areas, crop yields, and agricultural statistics (e.g., FAO reports).
• Forestry: Used for measuring forest extents, logging areas, and managing timber resources.
• Urban Planning and Land Management: Employed in zoning regulations, measuring park sizes, planning large-scale developments, and conducting environmental impact assessments across most metricated nations.
• Real Estate: The standard unit for large land parcels in most countries (though acres may persist alongside it in some Commonwealth nations transitioning from imperial).
• International Law and Treaties: Often used in legal definitions of land boundaries and resource allocation agreements (e.g., within the European Union).

Unit FAQs

How large is a hectare visually?

A hectare is 10,000 square meters. A square hectare is 100 meters by 100 meters. For comparison:

• It's slightly smaller than an international rugby union pitch (max 100m x 70m = 7,000 m²).
• It's about 1.4 times the size of a standard FIFA football (soccer) pitch (recommended 105m x 68m = 7,140 m²).
• London's Trafalgar Square is roughly one hectare in area.
• An American football field (including end zones) is about 0.535 hectares.

How many square meters are in a hectare?

There are exactly 10,000 square meters (m²) in one hectare (ha).

What is an "are" and how does it relate to a hectare?

The are (symbol: a) is another metric unit of area defined as 100 square meters (a square 10 meters by 10 meters). It was part of the original metric system. A hectare is equal to 100 ares. The are itself is rarely used today, but the hectare remains very common.

How many acres are in a hectare?

One hectare is approximately 2.471 acres. To convert hectares to acres, multiply by 2.471. Conversely, 1 acre is about 0.4047 hectares.

How many hectares are in a square kilometer?

There are exactly 100 hectares in one square kilometer (km²). This is because 1 km² = 1,000,000 m² and 1 ha = 10,000 m², so 1,000,000 / 10,000 = 100.

Is the hectare an official SI unit?

No, the hectare (ha) is not a base or derived unit within the International System of Units (SI). The SI unit for area is the square meter (m²). However, the hectare is listed by the International Bureau of Weights and Measures (BIPM) as a non-SI unit accepted for use with the SI due to its widespread practical importance, particularly in land measurement.