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Area
Square miles to Square kilometers
Convert square miles (mi²) to square kilometers (km²). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 mi² = 2.59 km²
Square miles to Square kilometers Conversion Table
Common values, ready to copy:
| square miles | square kilometers |
|---|---|
| 1 mi² | 2.59 km² |
| 2 mi² | 5.18 km² |
| 5 mi² | 12.9499 km² |
| 10 mi² | 25.8999 km² |
| 25 mi² | 64.7497 km² |
| 50 mi² | 129.5 km² |
| 100 mi² | 259 km² |
| 1,000 mi² | 2589.99 km² |
Formula
square kilometers = square miles × 2.58998811e+0
Area conversions are derived from length: 1 ft² = (0.3048 m)² = 0.092903 m². 1 acre = 4,046.86 m². 1 hectare = 10,000 m² exactly.
About Square miles and Square kilometers
Square miles (mi²): One mile squared, or 2.59 km²; the standard US unit for large land areas. Common uses: City and county area, state and national park sizes, watersheds, and large geographic features in the US.
Square kilometers (km²): One kilometer squared, or one million square meters. Common uses: City area, national park sizes, agricultural land, and geographic features at the regional scale.
How the conversion works
Area conversions are derived from length: 1 ft² = (0.3048 m)² = 0.092903 m². 1 acre = 4,046.86 m². 1 hectare = 10,000 m² exactly.
The exact relationship is square kilometers = square miles × 2.58998811e+0, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between square miles and square kilometers comes up wherever area measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.