Square miles to square kilometers (mi² to km²)
Convert square miles to square kilometers. For area, 1 mi² equals 2.58998811 km².
Converter
mi² to km² conversion table
| Square miles | Square kilometers |
|---|---|
| 1 mi² | 2.5899881 km² |
| 2 mi² | 5.1799762 km² |
| 5 mi² | 12.949941 km² |
| 10 mi² | 25.899881 km² |
| 25 mi² | 64.749703 km² |
| 50 mi² | 129.49941 km² |
| 100 mi² | 258.99881 km² |
| 1000 mi² | 2589.9881 km² |
Formula
km² = mi² × 2.58998811
Worked example
25 mi² × 2.58998811 = 64.74970276 km²
Popular conversion examples
Choose an example to open this converter with the value filled in. These are useful examples, not a claim about search rankings.
- 1 mi² to km² = 2.58999 km²
- 5 mi² to km² = 12.9499 km²
- 100 mi² to km² = 258.999 km²
- 10 mi² to km² = 25.8999 km²
- 1 km² to mi² = 0.386102 mi²
- 10 km² to mi² = 3.86102 mi²
About square miles and square kilometers
Square mile (mi²)
A square mile is 640 acres (about 2.59 square kilometers). It is used for the area of cities, parks and counties in the US and UK.
Square kilometer (km²)
A square kilometer is 1,000,000 square meters. It is used for the area of cities, countries and large regions.
Both are units of area; the base unit used internally is m².
Notes
- The acre is the international acre (4046.8564224 m²). The US survey acre differs by about 2 parts per million and is not included.
- Area cannot be negative.
mi² to km² FAQs
How do I convert square miles to square kilometers?
Multiply the number of square miles by 2.58998811 to get square kilometers. For example, 25 mi² × 2.58998811 = 64.7497 km².
How many square kilometers are in one square mile?
1 mi² = 2.58998811 km² and 1 km² = 0.3861021585 mi². To go the other way, use the square kilometers to square miles converter.
How many square kilometers are in 10 square miles?
10 mi² = 25.8999 km², rounded to 6 significant digits. Change the value in the converter above for any other amount.
Is the mi² to km² conversion exact?
The ratio is exact by definition, but its decimal form does not end (2.58998811034… to 12 significant digits). The converter keeps full precision internally and rounds only the displayed answer, which you can set from 4 to 12 significant digits.
What is the difference between square miles and square kilometers?
A square mile is 640 acres (about 2.59 square kilometers). It is used for the area of cities, parks and counties in the US and UK. A square kilometer is 1,000,000 square meters. It is used for the area of cities, countries and large regions.
Why isn't the mi² to km² factor the same as mi to km?
Area scales with the square of length. 1 mi = 1.609344 km, so 1 mi² = 1.609344² km² = 2.58998811 km².
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