Acre to Square Kilometer Converter
One Acre equals 0.004046856422 Square Kilometer (1 acre = 0.004046856422 km2). Multiply a Acre value by 0.004046856422 to get the equivalent in Square Kilometer. Use the calculator above for instant results, or follow the formula, worked examples, and reference table below.
Formula
km2 = acre × 0.004046856422
Multiply the Acre value by 0.004046856422 to get the equivalent value in Square Kilometer.
Example Conversions
1 Acre (acre)
0.004046856422 Square Kilometer (km2)
5 Acre (acre)
0.02023428211 Square Kilometer (km2)
10 Acre (acre)
0.04046856422 Square Kilometer (km2)
25 Acre (acre)
0.1011714106 Square Kilometer (km2)
100 Acre (acre)
0.4046856422 Square Kilometer (km2)
Conversion Table
| Acre (acre) | Square Kilometer (km2) |
|---|---|
| 0.1 | 0.0004046856422 |
| 0.5 | 0.002023428211 |
| 1 | 0.004046856422 |
| 2 | 0.008093712845 |
| 5 | 0.02023428211 |
| 10 | 0.04046856422 |
| 25 | 0.1011714106 |
| 50 | 0.2023428211 |
| 100 | 0.4046856422 |
| 250 | 1.011714106 |
| 500 | 2.023428211 |
| 1000 | 4.046856422 |
How to Convert Manually
Use these steps to convert Acre values to Square Kilometer without the calculator.
- Write down the value in Acre (acre) that you want to convert.
- Multiply that value by 0.004046856422.
- For example, 10 Acre × 0.004046856422 = 0.04046856422 Square Kilometer.
- Label the result as Square Kilometer (km2).
Relative Size Comparison
This chart shows the visual difference in size between exactly one Acre and one Square Kilometer.
About Acre and Square Kilometer
The acre is 43,560 square feet, exactly 4,046.8564224 square meters — historically the area a yoke of oxen could plow in a day. US and UK land sales still quote it. The square kilometer is one million square meters. Geography uses it for cities, lakes, parks, and countries — anything too large for hectares. One Acre equals 0.004046856422 Square Kilometer (1 acre = 0.004046856422 km2). Acre to Square Kilometer conversion comes up most often in US and UK land sales and in farm and ranch sizes in the US, typically when figures need restating for city and country land areas.
Precision and Rounding: Area factors are the squares of exact length factors, so they are exact too (1 ft² = 0.09290304 m² precisely). Whole numbers usually suffice for rooms and land parcels; surveying and legal land descriptions carry four or more decimal places.
Conversion factors per NIST Special Publication 811 and the BIPM SI Brochure (9th edition) (reference).
Worked Example
15 Acre equals 0.06070284634 Square Kilometer.
15 acre × 0.004046856422 = 0.06070284634 km2
FAQ
How do I convert Acre to Square Kilometer?
Multiply the Acre value by 0.004046856422 to get the equivalent value in Square Kilometer.
What is the formula for Acre to Square Kilometer?
The formula is km2 = acre × 0.004046856422.
How many Square Kilometer are in 1 Acre?
1 Acre equals 0.004046856422 Square Kilometer.
Can I convert Square Kilometer back to Acre?
Yes. 1 Square Kilometer equals 247.1053815 Acre, and the related converter can reverse the calculation.
What are common names for Acre and Square Kilometer?
Acre is shown as acre and may also be searched as acres. Square Kilometer is shown as km2 and may also be searched as square kilometers, sq km, km².
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