Acres to square kilometers
Type a value in acres to see it in square kilometers straight away, or type in the second box to convert back.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the acres box.
- Read the result in square kilometers as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
km² = ac × 0.004046856422
Multiply the value in acres by 0.004046856422 to get square kilometers.
Example
To convert 25 ac to square kilometers: 25 × 0.004046856422 = 0.101171 km².
Conversion table
| Acres (ac) | Square kilometers (km²) |
|---|---|
| 1 | 0.00404686 |
| 2 | 0.00809371 |
| 3 | 0.0121406 |
| 5 | 0.0202343 |
| 10 | 0.0404686 |
| 20 | 0.0809371 |
| 25 | 0.101171 |
| 50 | 0.202343 |
| 100 | 0.404686 |
| 250 | 1.01171 |
| 500 | 2.02343 |
| 1,000 | 4.04686 |
About the units
- Acre
- The international acre is 43,560 square feet, exactly 4046.8564224 square meters, used for land in the US and UK.
- Square kilometer
- A square kilometer is exactly 1,000,000 square meters, used for the area of cities and countries.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many square kilometers are in one acre?
1 ac = 0.00404686 km² exactly.
How do I convert acres to square kilometers?
Use km² = ac × 0.004046856422. For example, 25 ac = 0.101171 km².
How many acres are in one square kilometer?
1 km² = 247.105 ac.
How do I convert square meters to square feet?
Divide the square meters by 0.09290304, or multiply by about 10.7639. The factor is exact because a foot is exactly 0.3048 m.
Are the dunam, feddan and acre the same size?
No. A metric dunam is 1000 m², an Iraqi dunam 2500 m², an Egyptian feddan about 4200.83 m² and an acre 4046.8564224 m².