About the km² to ac calculation
One square kilometer is exactly 247.105 acres, so converting between them is a single multiplication. Enter any value above and the result updates as you type. The usual scale for reporting the area of cities and regions. The standard land unit in the US and UK — originally the area one ox team could plough in a day.
Formula
ac = km² × 247.105
1 km² = 247.105 ac
1 ac = 0.00404686 km²Worked example
To convert 1 km², multiply by 247.105: 1 × 247.105 = 247.105 ac.
Frequently asked questions
How many acres are in a square kilometer?
There are 247.105 acres in one square kilometer. To convert any amount, multiply the number of square kilometers by 247.105.
How do I convert acres back to square kilometers?
Divide instead of multiplying, or equivalently multiply by 0.00404686. One acre is 0.00404686 square kilometers.
Is this conversion exact?
Yes. Since the international agreement of 1959, the relationship between square kilometers and acres is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.
Where is each of these units used?
Square Kilometers: the usual scale for reporting the area of cities and regions. Acres: the standard land unit in the US and UK — originally the area one ox team could plough in a day.
Sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units