Surface area

This article explains the meaning of area as a physical quantity. The article area (geometry) is more mathematical.

Area is a quantity expressing the size of a region of space. Surface area refers to the summation of the areas of the exposed sides of an object.

Units

Units for measuring surface area include:

square metre = SI derived unit

are = 100 square metres

hectare = 10,000 square metres

square kilometre = 1,000,000 square metres

square megametre = 10¹² square metres

Imperial units, as currently defined from the metre:

square foot (plural square feet) = 0.09290304 square metres.

square yard = 9 square feet = 0.83612736 square metres

square perch = 30.25 square yards = 25.2928526 square metres

acre = 160 square perches or 43,560 square feet = 4046.8564224 square metres

square mile = 640 acres = 2.5899881103 square kilometres

The article Orders of magnitude links to lists of objects of comparable surface area.

Useful formulae

• Area of a rectangle (and, in particular, a square): length × width
• Area of a triangle: ½ × base × height
• Area of a disk: π × r²
• Area of a sphere: 4 × π × r²
• Total surface area of a right circular cylinder: 2 × π × r × (h + r)
• Lateral surface area of a right circular cylinder: 2 × π × r × h
• Total surface area of a right circular cone: π × r × (l + r)
• Lateral surface area of a right circular cone: π × r × l

External links

• Online Unit Converter - Conversion of many different units