Acre to Square kilometer Converter
1 ac = 0.004047 km² — convert instantly with formula and table.
Type a value above and it converts instantly — no button to press, no page reload, and the math runs entirely in your browser.
Quick answer: one acre equals 0.004047 square kilometers. So to convert acres to square kilometers, multiply by 0.00404686.
How to convert acres to square kilometers
square kilometers = acres × 0.0040468564
The acre — historically the area a yoke of oxen could plow in one day — equals 43,560 square feet and remains the standard US unit for land parcels.
The square kilometer (a million square meters) measures cities, lakes and countries — about 0.386 square miles.
Acre to Square kilometer conversion table
| Acre (ac) | Square kilometer (km²) |
|---|---|
| 0.01 ac | 0.00004047 km² |
| 0.1 ac | 0.00040469 km² |
| 0.25 ac | 0.001012 km² |
| 0.4 ac | 0.001619 km² |
| 0.75 ac | 0.003035 km² |
| 1.25 ac | 0.005059 km² |
| 1.75 ac | 0.007082 km² |
| 2.5 ac | 0.010117 km² |
| 3.5 ac | 0.014164 km² |
| 4.5 ac | 0.018211 km² |
| 6 ac | 0.024281 km² |
| 8 ac | 0.032375 km² |
| 10 ac | 0.040469 km² |
| 12 ac | 0.048562 km² |
| 14 ac | 0.056656 km² |
| 16 ac | 0.06475 km² |
| 18 ac | 0.072843 km² |
| 20 ac | 0.080937 km² |
| 24 ac | 0.097125 km² |
| 26 ac | 0.105218 km² |
| 30 ac | 0.121406 km² |
| 35 ac | 0.14164 km² |
| 45 ac | 0.182109 km² |
| 55 ac | 0.222577 km² |
| 65 ac | 0.263046 km² |
| 75 ac | 0.303514 km² |
| 85 ac | 0.343983 km² |
| 95 ac | 0.384451 km² |
| 110 ac | 0.445154 km² |
| 125 ac | 0.505857 km² |
| 175 ac | 0.7082 km² |
| 250 ac | 1.0117 km² |
| 350 ac | 1.4164 km² |
| 450 ac | 1.8211 km² |
| 600 ac | 2.4281 km² |
| 750 ac | 3.0351 km² |
| 900 ac | 3.6422 km² |
| 1,500 ac | 6.0703 km² |
| 2,500 ac | 10.1171 km² |
| 10,000 ac | 40.4686 km² |
Need the opposite direction? Use the Square kilometer to Acre converter, or read our complete guide to area conversions for every formula in one place.
Frequently asked questions
How many square kilometers are in one acre?
One acre equals 0.004047 square kilometers. Multiply any acre value by 0.00404686 to get square kilometers.
What is 10 acres in square kilometers?
10 acres equal 0.040469 square kilometers (10 × 0.004047).
Is the acre to square kilometer conversion exact?
The conversion factor used here (0.0040468564) is based on the internationally agreed definitions of both units, so results are exact up to rounding of the final decimal places.
Is my data stored when I use this converter?
No. The conversion runs entirely in your browser with JavaScript — nothing you type is sent to a server, logged or stored.