Square Kilometre

Square kilometre, symbol km2, is a decimal multiple of the SI unit of surface area, the square metre, one of the SI derived units. 1 km2 is equal to:

• 1,000,000 m2
• 100 ha (hectare)

It is also approximately equal to:

• 0.3861 square miles
• 247.1 acres

Conversely:

• 1 m2 = 0.000001 (10−6) km2
• 1 hectare = 0.01 (10−2) km2
• 1 square mile = 2.5899km2
• 1 acre = about 0.004047km2, 0.4047ha or 4047 m2

2.47 acres/ha

Note: "km2" means (km)2, square kilometre or kilometre squared and not k(m2), kilo–square metre. For example, 3 km2 is equal to 3×(1,000m)2 = 3,000,000 m2, not 3,000 m2.

Note also that if a piece of land, say a large park, is described as five kilometres square, that means it has the shape of a square, each side of the square being five kilometres long. This means that the park has an area of twenty-five square kilometres (and not five square kilometres).