Acres to Square Kilometers
An acre is 4,840 square yards, roughly the size of a football field, the traditional unit for land area in the US and UK. A square kilometer is one million square meters, used for city, country, and large land area comparisons. 1 ac equals ≈0.00404686 km², so converting between them is a matter of multiplying by that fixed factor — type any value into the converter below and both sides update instantly as you type.
Both units belong to area, measured here against area's base unit (m²) — every other area unit on this site converts through that same reference point, which is why the table below can also be read as a quick cross-check against nearby values.
Formula
km² = ac × ≈0.00404686
ac = km² × ≈247.105
Worked example: 5 ac × ≈0.00404686 = ≈0.0202343 km².
Conversion table
| Acre (ac) | Square Kilometer (km²) |
|---|---|
| 1 ac | ≈0.00404686 km² |
| 2 ac | ≈0.00809371 km² |
| 3 ac | ≈0.0121406 km² |
| 5 ac | ≈0.0202343 km² |
| 10 ac | ≈0.0404686 km² |
| 20 ac | ≈0.0809371 km² |
| 25 ac | ≈0.101171 km² |
| 50 ac | ≈0.202343 km² |
| 100 ac | ≈0.404686 km² |
| 250 ac | ≈1.01171 km² |
| 500 ac | ≈2.02343 km² |
| 1,000 ac | ≈4.04686 km² |
Frequently asked
- How many Square Kilometers in a acre?
- 1 ac equals ≈0.00404686 km².
- How do I convert Acres to Square Kilometers?
- Multiply the value in ac by ≈0.00404686 to get km². The converter above does this instantly as you type.
- Is the conversion exact?
- Yes — Acre and Square Kilometer are both defined by a fixed conversion factor to area's base unit (m²), so the result shown is exact to the precision displayed, not an approximation.