How to convert acres to square kilometers
km² = ac × 0.004046856422Multiply the value in acres by 0.004046856422. To go the other way, multiply by 247.1053815 (or divide by 0.004046856422).
An acre is smaller than a square kilometer: it takes 247.1053815 acres to make one square kilometer.
Worked examples
- 1 acre1 ac × 0.004046856422 = 0.004046856422 km²
- 5 acres5 ac × 0.004046856422 = 0.02023428211 km²
- 10 acres10 ac × 0.004046856422 = 0.04046856422 km²
- 20 acres20 ac × 0.004046856422 = 0.08093712845 km²
- 100 acres100 ac × 0.004046856422 = 0.4046856422 km²
Acres to square kilometers conversion table
Values are calculated by the conversion engine and rounded to 8 significant figures.
| Acres (ac) | Square kilometers (km²) |
|---|---|
| 0.1 ac | 0.00040468564 km² |
| 0.25 ac | 0.0010117141 km² |
| 0.5 ac | 0.0020234282 km² |
| 1 ac | 0.0040468564 km² |
| 2 ac | 0.0080937128 km² |
| 3 ac | 0.012140569 km² |
| 4 ac | 0.016187426 km² |
| 5 ac | 0.020234282 km² |
| 6 ac | 0.024281139 km² |
| 7 ac | 0.028327995 km² |
| 8 ac | 0.032374851 km² |
| 9 ac | 0.036421708 km² |
| 10 ac | 0.040468564 km² |
| Acres (ac) | Square kilometers (km²) |
|---|---|
| 12 ac | 0.048562277 km² |
| 15 ac | 0.060702846 km² |
| 20 ac | 0.080937128 km² |
| 25 ac | 0.10117141 km² |
| 30 ac | 0.12140569 km² |
| 40 ac | 0.16187426 km² |
| 50 ac | 0.20234282 km² |
| 75 ac | 0.30351423 km² |
| 100 ac | 0.40468564 km² |
| 250 ac | 1.0117141 km² |
| 500 ac | 2.0234282 km² |
| 1,000 ac | 4.0468564 km² |
About the units
Acre (ac)
43,560 ft² (4,046.8564224 m²). Historically the land one ox team could plough in a day; still the US and UK unit for land parcels.
Square kilometer (km²)
One million square metres or 100 hectares; used for city, lake and country areas. One square kilometer equals 1,000,000 square meters (m²).
Frequently asked questions
How many square kilometers are in one acre?
There are 0.004046856422 square kilometers in one acre, and this value is exact by definition.
How do I convert acres to square kilometers?
Multiply the number of acres by 0.004046856422. For example, 10 ac × 0.004046856422 = 0.04046856422 km².
How many acres are in one square kilometer?
One square kilometer equals 247.1053815 acres. That is the reverse factor, 1 ÷ 0.004046856422.
What is 10 acres in square kilometers?
10 ac = 0.04046856422 km².
Is this ac to km² converter accurate?
Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.