Acre to Square Kilometer Converter (ac to km²)
1 acre equals 0.00404686 square kilometers — multiply the number of acres by 0.00404686 to convert. Because a square kilometer is a very large area, an acre is only a tiny fraction of one.
The formula
To convert acres to square kilometers, multiply by 0.00404686:
square kilometers = acres × 0.00404686
For example, 10 ac × 0.00404686 = 0.0404686 km². To reverse it, divide by 0.00404686 (or multiply by 247.105381).
Conversion table
| Acres (ac) | Square kilometers (km²) |
|---|---|
| 1 | 0.00404686 |
| 2 | 0.00809372 |
| 3 | 0.01214058 |
| 5 | 0.0202343 |
| 10 | 0.0404686 |
| 25 | 0.1011715 |
| 50 | 0.202343 |
| 100 | 0.404686 |
| 500 | 2.02343 |
| 1000 | 4.04686 |
How to convert online
- Type the number of acres into the first box.
- Read the square-kilometer value instantly in the second box.
- Enter a km² value to convert back to acres — it works both ways.
Use the Acre to Square Kilometer Converter — free and instant in your browser.
Where this conversion is used
Large-scale land, mapping and environmental work reports area in square kilometers, while farmland and property deeds often use acres. Converting helps when sizing estates, nature reserves or development sites against regional maps and GIS data that use metric units.
FAQ
How many square kilometers are in an acre?
One acre equals 0.00404686 km². So 100 acres is 0.404686 km² and 1000 acres is 4.04686 km².
How do I convert square kilometers back to acres?
Divide by 0.00404686, or multiply by 247.105381. So 1 km² is about 247.11 acres.
Is the conversion exact?
The factor is rounded to 0.00404686 for display; it derives from the exact acre value of 4046.8564224 m². For everyday use it is accurate to the shown precision.
Is this converter free and private?
Yes. It runs entirely in your browser — nothing is uploaded or stored. It is free, needs no sign-up and works offline once loaded.
Related converters
- Square Kilometer to Acre Converter
- Acre to Square Meter Converter
- Acre to Square Mile Converter
- Acre to Hectare Converter
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