Instant · Precise · Universal
23 units available
6 categories total
To convert km² to mi²: multiply by 0.3861. To hectares: multiply by 100. To acres: multiply by 247.105.
1 km² = 1,000,000 m² = 100 ha = 247.105 acres ≈ 0.3861 mi².
For example, 1 Square Kilometer (km²) = 247.104393 Acre (US Survey) (ac (US)).
| Square Kilometer (km²) | Acre (US Survey) (ac (US)) |
|---|---|
| 0.1 | 24.7104393 |
| 0.5 | 123.5521965 |
| 1 | 247.104393 |
| 2 | 494.2087861 |
| 5 | 1235.521965 |
| 10 | 2471.04393 |
| 25 | 6177.609826 |
| 50 | 12355.21965 |
| 100 | 24710.4393 |
| 500 | 123552.1965 |
| 1000 | 247104.393 |
The square kilometer is a metric unit of area equal to 1,000,000 square meters, or a square with sides of 1 kilometer.
1 km² = 1,000,000 m² = 100 ha = 247.105 acres ≈ 0.3861 mi².
To convert km² to mi²: multiply by 0.3861. To hectares: multiply by 100. To acres: multiply by 247.105.
Country areas, national park sizes, city footprints, forest coverage, and watershed boundaries.
Vatican City = 0.44 km². Manhattan = 59.1 km². Russia = 17,098,242 km² (largest country). Earth's surface = 510,072,000 km².
Thinking 1 km² = 1,000 m² (it's actually 1,000,000 m²). Area scales as the square of the linear dimension.
1 km = 1,000 m, but 1 km² = 1,000² m² = 1,000,000 m². Always square the conversion factor for area.
The US survey acre is a historical unit of area based on the US survey foot, equal to approximately 4,046.873 m².
1 US survey acre ≈ 4,046.873 m². Differs from international acre (4,046.856 m²) by about 0.016 m².
To convert US survey acres to m²: multiply by 4,046.873. To international acres: multiply by ~1.000004.
Historical US land surveys, old property deeds, and State Plane Coordinate System calculations.
The difference between US survey and international acre is about 0.016 m² — roughly the area of a sheet of paper. Over large areas, it adds up.
Using US survey acre in new calculations — it's been deprecated since 2023. Use the international acre instead.
As of 2023, the US survey foot and acre are retired. All US measurements now use the international definitions.



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