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acre (acre) → square kilometer (km2)

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Use our free online converter to convert between units instantly. Enter any value in the field above to get accurate results. No signup or download required—all conversions run in your browser. Our calculator uses standard conversion factors for reliability.

0
acre=km2
0.01=0
0.1=0.000405
1=0.004047
2=0.008094
3=0.012141
5=0.020234
10=0.040469
20=0.080937
50=0.202343
100=0.404686
1000=4.04686

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Brief explanation: acre to square kilometer

Square meter is the base unit for area. Hectare = 10,000 m². Acre ≈ 4047 m². Square foot = 0.093 m². Square km = 1 million m². Area measures two-dimensional space. Hectares are used for land (farms, parks). Acres are common in the US and UK for real estate. Square feet are standard for room sizes. When converting, remember area uses squared units—so 1 m² = 10.76 ft².

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Common conversion examples: acre to square kilometer

Reference values for quick comparison. Use the converter above for any amount.

  • 1 acre=0.004 square kilometer
  • 10 acre=0.0405 square kilometer
  • 100 acre=0.4047 square kilometer

About the Units

acre (acre)

Definition: An acre is a unit of area used in the imperial and US systems. One acre equals 4,046.86 square meters or about 0.405 hectares. It was traditionally the area a yoke of oxen could plow in a day.
History: The acre has medieval English origins. It was standardized for land measurement and taxation. The international acre was defined in 1959 for consistency.
Current use: Acres are used for land area in the US, UK, and some Commonwealth countries. Real estate, farming, and forestry use acres. Most countries use hectares.

square kilometer (km2)

Definition: A square kilometer (km²) is a unit of area equal to 1,000,000 square meters. It is used for large areas such as cities, countries, and lakes.
History: The square kilometer emerged for geographical and administrative areas. It simplified expression of large land areas without excessive zeros.
Current use: Square kilometers are used for country size, city area, and park size. Geographical and demographic data use km². One km² is about 0.386 square miles.

Sources

Conversion factors and unit definitions follow international standards. For authoritative references, see: