Square Miles to km2 Converter
1 square mile = 2.58999 km2. Used for US state and county areas.
Formula:1 mi2 = 2.58999 km2
Quick conversion table — Sq. mile to Sq. kilometer
0.5 mi²1.294994 km²
1 mi²2.589988 km²
2 mi²5.179976 km²
5 mi²12.94994 km²
10 mi²25.89988 km²
20 mi²51.79976 km²
50 mi²129.4994 km²
100 mi²258.9988 km²
500 mi²1,294.994 km²
1,000 mi²2,589.988 km²
How to convert mi2 to km2
To convert square miles to square km, use the formula: 1 mi2 = 2.58999 km2. Simply enter the value you want to convert in the field above and the result appears instantly. You can also type in the result field to reverse the conversion.
All conversions use precise mathematical constants validated against international SI standards (NIST and ISO 80000). Results are accurate to 8 significant figures.
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