Square Kilometers to Square Miles Converter (km² to mi²)
1 km² ≈ 0.386102 mi². Convert square kilometers to square miles for cities, countries, wildfires and map grids, with km² and mi² charts.
Square Mile (mi²) = Square Kilometer (km²) × 0.386102158542
Square Kilometer (km²): A square kilometre is the area of a square 1 km on each side: 1 000 000 m², or 100 hectares. It is used for the area of cities, lakes, countries and other large regions.
Square Mile (mi²): A square mile is the area of a square 1 mile on each side: 640 acres, or exactly 2.589988110336 km². It is used in the US and UK for the area of cities, counties and states.
| Square Kilometer (km²) | Square Mile (mi²) |
|---|---|
| 1 | 0.386102158542 |
| 5 | 1.93051079271 |
| 10 | 3.86102158542 |
| 25 | 9.65255396356 |
| 50 | 19.3051079271 |
| 100 | 38.6102158542 |
Square kilometers are the standard unit for the size of cities, countries, islands, lakes and wildfire burn areas in most of the world, and in figures published by international bodies. American readers, used to square miles, often want the number translated. One square kilometer is a square 1,000 m on each side, or 100 hectares, and about 0.3861 square miles, so the mile figure is a little under two fifths of the kilometer figure.
Large areas are where the conversion matters most, because a factor of nearly 2.6 separates the two numbers. A country of 100,000 km² sounds far bigger than one of 40,000 sq mi, yet the two are almost the same size. Map grids are a practical case too: Britain's Ordnance Survey grid and the UTM grid on many topographic maps divide the sheet into 1 km squares, each covering about 0.386 mi².
How to use this tool
- Type a value in the Square Kilometer box to see it in square miles, or type in the Square Mile box to convert the other way.
- Press ⇄ to swap the two units, or Load example for a typical value.
- Check the charts below for common values; for other units, open the Area converter.
Formula
Square Mile (mi²) = Square Kilometer (km²) × 0.386102158542
Square Kilometer (km²) = Square Mile (mi²) × 2.58998811034
Both factors come from exact definitions: 1 square mile = 2.58998811034 square kilometers and 1 square kilometer = 0.386102158542 square miles (shown to 12 significant digits).
Example
Two conversions worked with the same factors the converter uses:
605.2 km² × 0.386102158542 ≈ 233.669 mi²
250 mi² × 2.58998811034 ≈ 647.497 km²
Square Kilometer to Square Mile chart
Common values from square kilometers to square miles, rounded to four decimal places.
| Square Kilometer (km²) | Square Mile (mi²) |
|---|---|
| 0.5 | 0.1931 |
| 1 | 0.3861 |
| 2 | 0.7722 |
| 2.59 | 1 |
| 5 | 1.9305 |
| 10 | 3.861 |
| 20 | 7.722 |
| 25 | 9.6526 |
| 50 | 19.3051 |
| 100 | 38.6102 |
| 150 | 57.9153 |
| 200 | 77.2204 |
| 250 | 96.5255 |
| 500 | 193.0511 |
| 750 | 289.5766 |
| 1,000 | 386.1022 |
| 2,000 | 772.2043 |
| 5,000 | 1,930.51 |
| 10,000 | 3,861.02 |
| 20,000 | 7,722.04 |
| 50,000 | 19,305.11 |
| 100,000 | 38,610.22 |
| 1,000,000 | 386,102.16 |
Square Mile to Square Kilometer chart
The reverse direction for values people often look up.
| Square Mile (mi²) | Square Kilometer (km²) |
|---|---|
| 0.5 | 1.295 |
| 1 | 2.59 |
| 2 | 5.18 |
| 5 | 12.9499 |
| 10 | 25.8999 |
| 36 | 93.2396 |
| 50 | 129.4994 |
| 100 | 258.9988 |
| 250 | 647.497 |
| 500 | 1,294.99 |
| 1,000 | 2,589.99 |
| 5,000 | 12,949.94 |
| 10,000 | 25,899.88 |
| 100,000 | 258,998.81 |
Areas given in square kilometers
| Area | Square Kilometer (km²) | Square Mile (mi²) |
|---|---|---|
| Square on a 1 km map grid | 1 | 0.3861 |
| Ordnance Survey 10 km grid square, Great Britain | 100 | 38.6102 |
| Paris, inside the city limits | 105.4 | 40.6952 |
| Seoul, total city area | 605.2 | 233.669 |
| Ordnance Survey 100 km grid square | 10,000 | 3,861.02 |
| Russia, the largest country by area | 17,098,246 | 6,601,669.69 |
Quick mental estimate
Multiply by 0.4, then trim about 3.5%: 605 km² → 242 → about 234 mi². The 0.4 step alone is 3.6% above the exact 0.3861; the exact figure for 605 km² is 233.6 mi².
Use the converter or the charts when the exact figure matters.
The two units
Square Kilometer (km²): A square kilometre is the area of a square 1 km on each side: 1 000 000 m², or 100 hectares. It is used for the area of cities, lakes, countries and other large regions.
Square Mile (mi²): A square mile is the area of a square 1 mile on each side: 640 acres, or exactly 2.589988110336 km². It is used in the US and UK for the area of cities, counties and states.
Frequently asked questions
How many square miles is 1 square kilometer?
About 0.3861 mi² (0.386102). Turned around, a square mile is about 2.59 km², so it takes roughly two and a half square kilometers to cover one square mile.
How do I compare the area of a foreign city with a US city?
Put both figures in the same unit, and check that both are land areas or both include water. City limits also differ in what they take in, so a larger number does not always mean a larger built-up area.
Why is the km² figure always bigger than the mi² figure?
Because the square kilometer is the smaller unit. A kilometer is about 0.62 mile, and squaring that gives about 0.386, so the same land takes about 2.59 times as many square kilometers as square miles.
How precise is the result?
The converter uses the exact definitions above with browser floating-point arithmetic and shows up to 12 significant digits. The charts round to four decimal places for reading.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/square-kilometer-to-square-mile-converter/
Cite or embed this tool
kakaoCalc. (2026, November 8). Square Kilometers to Square Miles Converter (km² to mi²). https://kakao.mobile/tools/square-kilometer-to-square-mile-converter/
“Square Kilometers to Square Miles Converter (km² to mi²).” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/square-kilometer-to-square-mile-converter/.
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