Square Miles to Square Kilometers Converter
Convert square miles to square kilometers instantly. One square mile equals exactly 2.589988 square kilometers. Type in either box to convert both ways, then use the chart, worked examples and everyday sizes below.
How to convert square miles to square kilometers
Worked example: convert 15 square miles to square kilometers. Using square kilometers ← square miles × 2.58998811, we get 15 × 2.58998811 = 38.849822 km². To check the result, convert back: 38.849822 km² ÷ 2.58998811 = 15 sq mi.
Square miles to square kilometers chart
| Square miles (sq mi) | Square kilometers (km²) |
|---|---|
| 1 sq mi | 2.589988 km² |
| 2 sq mi | 5.179976 km² |
| 3 sq mi | 7.769964 km² |
| 4 sq mi | 10.35995 km² |
| 5 sq mi | 12.94994 km² |
| 6 sq mi | 15.53993 km² |
| 8 sq mi | 20.7199 km² |
| 10 sq mi | 25.89988 km² |
| 12 sq mi | 31.07986 km² |
| 15 sq mi | 38.84982 km² |
| 20 sq mi | 51.79976 km² |
| 25 sq mi | 64.7497 km² |
| 30 sq mi | 77.69964 km² |
| 40 sq mi | 103.5995 km² |
| 50 sq mi | 129.4994 km² |
| 75 sq mi | 194.2491 km² |
| 100 sq mi | 258.9988 km² |
| 150 sq mi | 388.4982 km² |
| 200 sq mi | 517.9976 km² |
| 250 sq mi | 647.497 km² |
| 500 sq mi | 1,294.994 km² |
| 1,000 sq mi | 2,589.988 km² |
Square kilometers to square miles (reverse)
| Square kilometers (km²) | Square miles (sq mi) |
|---|---|
| 1 km² | 0.3861022 sq mi |
| 2 km² | 0.7722043 sq mi |
| 5 km² | 1.930511 sq mi |
| 10 km² | 3.861022 sq mi |
| 20 km² | 7.722043 sq mi |
| 50 km² | 19.30511 sq mi |
| 100 km² | 38.61022 sq mi |
| 250 km² | 96.52554 sq mi |
| 500 km² | 193.0511 sq mi |
| 1,000 km² | 386.1022 sq mi |
About the square mile and the square kilometer
A square mile is 640 acres. It is used for county, city and country areas in the United States and United Kingdom; Manhattan covers about 23 square miles of land.
A square kilometer is one million square meters, or 100 hectares. It describes cities, lakes and countries; Monaco covers about 2 km².
One square mile equals 2.589988 square kilometers, which makes the square mile the larger unit of the two.
Everyday sizes in square miles and square kilometers
| Everyday example (approximate) | In square miles | In square kilometers |
|---|---|---|
| A basketball court | 0.00016857 sq mi | 0.0004366 km² |
| A soccer pitch | 0.0027568 sq mi | 0.00714 km² |
| A hectare | 0.003861 sq mi | 0.01 km² |
| Vatican City | 0.16988 sq mi | 0.44 km² |
| Central Park in New York | 1.3166 sq mi | 3.41 km² |
| Manhattan (land area) | 22.819 sq mi | 59.1 km² |
Square miles to square kilometers FAQ
How many square kilometers are in one square mile?
One square mile equals exactly 2.58998811 square kilometers. In the other direction, one square kilometer equals 0.38610216 square miles.
How do I convert square miles to square kilometers without a calculator?
convert 15 square miles to square kilometers. Using square kilometers ← square miles × 2.58998811, we get 15 × 2.58998811 = 38.849822 km². To check the result, convert back: 38.849822 km² ÷ 2.58998811 = 15 sq mi. For a quick estimate, round the factor to 2.6. Then 15 sq mi is about 39 km², compared with the exact 38.8498 km² (an error of 0.39%). That is close enough for planning, but use the calculator above when the number matters.
What is a hectare in square kilometers?
A hectare is about 0.003861 square miles, which is 0.01 square kilometers. Treat that as an approximate everyday figure rather than an official measurement.
Are the square miles and square kilometers the same in every country?
The square mile is exactly 2,589,988.110336 m² and equals 640 acres. The square kilometer is exactly 1,000,000 m².