**Area** is a measure of the extension of a surface expressed in units known as surface units. For flat surfaces the concept is more intuitive. Any flat surface with straight sides can triangulate and its area can be calculated as the sum of the areas of these triangles. The term "Area is cccasionally used as a synonym for surface, when there is no confusion between the geometrical concept itself (surface) and the magnitude metric associated to geometric concept (area).

However, to calculate the curved surface area is required to introduce methods of differential geometry.

To define the area of a surface in general (which is a metric concept), it has to be defined a metric tensor on the surface in question: when the surface is in a Euclidean space, the surface naturally inherits a metric structure induced by the Euclidean metric.

- acre
- acre [suburbs]
- acre [survey]
- acre [Ireland]
- are
- arpent [Canada]
- barn
- bovate
- bunder
- caballeria [Spain/Peru]
- caballeria [Central America]
- caballeria [Cuba]
- carreau
- carucate
- cawney
- centiare
- cong
- cover
- cuerda
- dekare
- dessiatina
- dhur
- dunum, dunham
- fall [Scots]
- fall [English]
- fanega
- farthingdale
- hacienda
- hectare
- hide
- homestead
- hundred
- jerib
- jitro, joch, jutro
- jo [Japan]
- kappland
- kattha [Nepal]
- labor
- legua
- manzana [Costa Rican]
- manzana [Argentina]
- manzana [Nicaragua]
- morgen [Germany]
- morgen [South Africa]
- mu
- ngarn
- nook
- oxgang
- perch
- perche [Canada]
- ping
- pyong
- rai
- rood
- section
- shed
- sitio
- square
- square angstrom
- square astronomical unit
- square attometer
- square bicron
- square centimeter
- square chain [Gunter, survey]
- square chain [Ramden, Engineer]
- square city block [East U.S.]
- square city block [Midwest U.S.]
- square city block [South, West U.S.]
- square cubit
- square decimeter
- square dekameter
- square exameter
- square fathom
- square femtometer
- square fermi
- square foot
- square foot [survey]
- square furlong
- square gigameter
- square hectometer
- square inch
- square inch [survey]
- square kilometer
- square league [nautical]
- square league [U.S. statute]
- square light year
- square link [Gunter, survey]
- square link [Ramden, Engineer]
- square megameter
- square meter
- square microinch
- square micrometer
- square micromicron
- square micron
- square mil
- square mile
- square mile [nautical]
- square mile [survey, U.S. statute]
- square millimeter
- square millimicron
- square myriameter
- square nanometer
- square Paris foot
- square parsec
- square perch
- square perche
- square petameter
- square picometer
- square rod
- square tenthmeter
- square terameter
- square thou
- square vara [California]
- square vara [Texas]
- square yard
- square yard [survey]
- square yoctometer
- square yottameter
- stang
- stremma
- tarea
- tatami [Japan]
- tønde land
- township
- tsubo
- tunnland
- yard
- virgate

Click on the unit you **want** to convert