The square metre (also spelled square meter, see spelling differences) is the SI derived unit of area, with symbol m^{2} (33A1 in Unicode^{[1]}). It is defined as the area of a square whose sides measure exactly one metre. The square metre is derived from the SI base unit of the metre, which in turn is defined as the length of the path travelled by light in absolute vacuum during a time interval of ^{1}⁄_{299,792,458} of a second.
Adding and multiplying SI prefixes creates multiples and submultiples; however, as the unit is squared, the order of magnitude difference between units doubles from their comparable linear units. For example, a kilometre is one thousand times the length of a metre, but a square kilometre is one million times the area of a square metre.
Square metres are not necessarily the same as meters squared^{[2]}: an area 2 metres wide by 5 metres long would be 10 square metres, while 10 metres squared means an area of 10 metres by 10 metres. So 10 metres squared equals 100 square meters.
Contents 
The square metre may be used with all SI prefixes used with the metre.
Multiplication  Name  Symbol  plusing  Name  Symbol  

10^{0}  square metre (centiare)  m^{2}  10^{0}  square metre (centiare)  m^{2}  
10^{2}  square decametre (are)  dam^{2}  10^{–2}  square decimetre  dm^{2}  
10^{4}  square hectometre (hectare)  hm^{2}  10^{–4}  square centimetre  cm^{2}  
10^{6}  square kilometre  km^{2}  10^{–6}  square millimetre  mm^{2}  
10^{12}  square megametre  Mm^{2}  10^{–12}  square micrometre  µm^{2}  
10^{18}  square gigametre  Gm^{2}  10^{–18}  square nanometre  nm^{2}  
10^{24}  square terametre  Tm^{2}  10^{–24}  square picometre  pm^{2}  
10^{30}  square petametre  Pm^{2}  10^{–30}  square femtometre  fm^{2}  
10^{36}  square exametre  Em^{2}  10^{–36}  square attometre  am^{2}  
10^{42}  square zettametre  Zm^{2}  10^{–42}  square zeptometre  zm^{2}  
10^{48}  square yottametre  Ym^{2}  10^{–48}  square yoctometre  ym^{2} 
A square metre is equal to:
Orders of magnitude for area  

1 E30 m² = 1 fm^{2}  1 E24 m² = 1 pm^{2}  1 E18 m² = 1 nm^{2}  1 E12 m² = 1 µm^{2}  1 E6 m² = 1 mm^{2}  1 E0 m² = 1 m^{2}  1 E+6 m² = 1 km^{2}  1 E+12 m² = 1 Mm^{2}  1 E+1824 m² : 1 Gm^{2} 
10 fm^{2}  10 pm^{2}  10 nm^{2}  10 µm^{2}  10 mm^{2}  10 m^{2}  10 km^{2}  10 Mm^{2}  > 1 E+24 m² : 1 Tm² 
100 fm^{2}  100 pm^{2}  100 nm^{2}  100 µm^{2}  100 mm^{2} = 1 cm^{2}  100 m^{2} = 1 a  100 km^{2}  100 Mm^{2}  
1,000 fm^{2}  1,000 pm^{2}  1,000 nm^{2}  1,000 µm^{2}  10 cm^{2}  10 a  1,000 km^{2}  1,000 Mm^{2}  
10,000 fm^{2}  10,000 pm^{2}  10,000 nm^{2}  10,000 µm^{2}  100 cm^{2}  10,000 m^{2} = 1 ha  10,000 km^{2}  10,000 Mm^{2}  
100,000 fm^{2}  100,000 pm^{2}  100,000 nm^{2}  100,000 µm^{2}  1,000 cm^{2}  10 ha  100,000 km^{2}  100,000 Mm^{2}  
SI derived unit square metre, from base unit metre  Conversion of units for area 
The square metre (also spelled square meter, see spelling differences) is the SI derived unit of area, with symbol m²(33A1 in Unicode^{[1]}). It is defined as the area of a square whose sides measure exactly one metre. The square metre is derived from the SI base unit of the metre, which in turn is defined as the length of the path travelled by light in absolute vacuum during a time interval of ^{1}⁄_{299,792,458} of a second.
Adding SI prefixes creates multiples and submultiples; however, as the unit is squared, the order of magnitude difference between units doubles from their comparable linear units. For example, a kilometre is one thousand times the length of a metre, but a square kilometre is one million times the area of a square metre.
A square metre is not the same as a meter square^{[2]}, an area 2 metres wide by 5 metres long would be 10 square metres, in contrast 10 metres squared means an area 10 metres by 10 metres. So 10 metres squared = 100 Square meteres.
Contents 
The square metre may be used with all SI prefixes used with the metre.
Multiple  Name  Symbol  Multiple  Name  Symbol  

10^{0}  square metre (centiare)  m²  10^{0}  square metre (centiare)  m²  
10^{2}  square decametre (are)  dam²  10^{–2}  square decimetre  dm²  
10^{4}  square hectometre (hectare)  hm²  10^{–4}  square centimetre  cm²  
10^{6}  square kilometre  km²  10^{–6}  square millimetre  mm²  
10^{12}  square megametre  Mm²  10^{–12}  square micrometre  µm²  
10^{18}  square gigametre  Gm²  10^{–18}  square nanometre  nm²  
10^{24}  square terametre  Tm²  10^{–24}  square picometre  pm²  
10^{30}  square petametre  Pm²  10^{–30}  square femtometre  fm²  
10^{36}  square exametre  Em²  10^{–36}  square attometre  am²  
10^{42}  square zettametre  Zm²  10^{–42}  square zeptometre  zm²  
10^{48}  square yottametre  Ym²  10^{–48}  square yoctometre  ym² 
A square metre is equal to:


