Direct conversion
Convert acre [ac] to square kilometer [km²] instantly with formula, examples, chart, and FAQs.
1 acre [ac] = 0.004047 square kilometer [km²]
1 acre [ac] = 0.004047 square kilometer [km²]
Example: 1 acre [ac] equals 0.004047 square kilometer [km²].
Area conversions are derived from squared length relationships, using square metre as the reference unit and fixed factors such as 1 square foot = 0.09290304 square metre.
Displayed results are rounded for readability. The calculator keeps enough precision for everyday use and switches to scientific notation for very large or very small values. Last reviewed: 2026-05-21.
The acre is a land area unit equal to 43,560 square feet or about 4046.856 square meters.
HistoryThe acre has agricultural origins and became a standard land measure in customary systems.
Current useAcres are used for land parcels, farms, real estate, parks, and property planning.
The square kilometer (km²) is a area unit used to express measurements in this converter.
HistoryThis unit is included because it appears in practical measurement systems, technical references, product specifications, or everyday conversion needs.
Current useUse square kilometer when comparing area values, checking specifications, converting between systems, or preparing quick estimates.
| acre [ac] | square kilometer [km²] |
|---|---|
| 1 | 0.004047 |
| 2 | 0.008094 |
| 5 | 0.020234 |
| 10 | 0.040469 |
| 20 | 0.080937 |
| 25 | 0.101171 |
| 50 | 0.202343 |
| 100 | 0.404686 |
| 1000 | 4.046856 |
Use this formula: 1 acre [ac] = 0.004047 square kilometer [km²] Enter your value in the calculator and the result updates instantly.
1 acre [ac] equals 0.004047 square kilometer [km²].
Yes. Use the swap button in the calculator or open the related reverse conversion link when it is listed on this page.