A unit of area , also area unit or more precisely unit of area , is understood to be a unit of measurement for specifying the area of an area . A surface measure is used to measure or specify the content of an area in two dimensions , such as the surface of a body .
The determination of the content of an area ( planimetry ) can be done by determining how often a unit of area is contained in this area. A rectangle with side lengths a = 5 m and b = 3 m therefore has an area of A = 15 m 2 . In the designation m 2 , the superscript number 2 means that there are two dimensions: length and width.
According to the international system , the area dimensions are derived from the meter and its parts as well as multiples in accordance with the meter convention . The basic unit is the square meter : 1 m 2 is the area of a square with a side length of 1 m.
Depending on the application, larger or smaller surface units are used. The following table provides an overview:
|Square kilometre||1000 m x 1000 m||1,000,000 m 2||km 2|
|Hectares||100 m x 100 m||10,000 m 2||Ha|
|Ar||10 m 10 m||100 m 2||a|
|square meters||1 m x 1 m||1 m 2||m 2|
|Square decimeters||0.1m x 0.1m||0.01 m 2||dm 2|
|Square centimeters||0.01m x 0.01m||0.0001 m 2||cm 2|
|Square millimeters||0.001 m by 0.001 m||0.000001 m 2||mm 2|
Other square measures still used today are: barn , square inches , square feet , square mile , acre , dunam , acre , rai , pyeong . Information on the area dimensions that were used in the past can be found in the article " Old dimensions and weights ". The article “ Size (area) ” provides an overview of objects of various dimensions .