Area
system unit code
(alternative)
QID symbol or
abbrev.
notes sample
default conversion
combinations
SI square kilometre km2 Q712226 km2 US spelling: square kilometer
1.0 km2 (0.39 sq mi)
  • km2 sqmi
square hectometre hm2 Q35852 hm2 US spelling: square hectometer
1.0 hm2 (2.5 acres)
square decametre dam2 Q23931040 dam2 US spelling: square dekameter
1.0 dam2 (1,100 sq ft)
square metre m2 Q25343 m2 US spelling: square meter
1.0 m2 (11 sq ft)
  • m2 sqft
square decimetre dm2 Q3331719 dm2 US spelling: square decimeter
1.0 dm2 (16 sq in)
square centimetre cm2 Q2489298 cm2 US spelling: square centimeter
1.0 cm2 (0.16 sq in)
  • cm2 sqin
square millimetre mm2 Q2737347 mm2 US spelling: square millimeter
1.0 mm2 (0.0016 sq in)
  • mm2 sqin
non-SI metric hectare ha Q35852 ha equivalent to one square hectometre 1.0 ha (2.5 acres)
Imperial
&
US customary
square mile sqmi Q232291 sq mi 1.0 sq mi (2.6 km2)
  • sqmi km2
acre acre Q81292 (none) 1.0 acre (0.40 ha)
square yard sqyd Q1550511 sq yd 1.0 sq yd (0.84 m2)
square foot sqft
(ft2, sqfoot, foot2)
Q857027 sq ft long code "sqfoot (foot2)" outputs square foot (and never feet) 1.0 sq ft (0.093 m2)
  • sqft m2
square inch sqin Q1063786 sq in 1.0 sq in (6.5 cm2)
  • sqin cm2
  • sqin mm2
Maritime units square nautical mile sqnmi (nmi2) Q23931103 sq nmi 1.0 sq nmi (3.4 km2; 1.3 sq mi)
Middle Eastern dunam dunam (metric dunam) Q23931109 (none) The spellings dunum, donum and dönüm are also acceptable variants. Just replace dunam with the desired spelling in the code. The spelling dönüm also results from using donum diaeresis or donum dots. 1.0 dunam (0.0010 km2; 0.00039 sq mi)


Japanese tsubo tsubo Q23931147 (none) 1.0 tsubo (3.3 m2)
Korean pyeong pyeong Q706688 (none) 1.0 pyeong (3.3 m2)
Spanish cuerda cda Q23931245 cda 1.0 cda (0.39 ha; 0.97 acres)