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Square Miles to Square Kilometers Converter

Convert square miles (sq mi) to square kilometers (km²), with the formula, a conversion table and exact factors.

Change the values and press Calculate to work out your own figures.

Enter an area, choose its unit and the unit you want. The answer is exact until it is shown, and the same value appears in every other unit.

A number, fraction (3/8), mixed number (1 1/2), scientific notation (2.5e6) or a simple sum such as 2*3.
The unit you want the answer in. Swap exchanges the two units.
Result
2.58998811034 km²
acres
640 ac
square yards
3,097,600 sq yd
square feet
27,878,400 sq ft
square inches
4,014,489,600 sq in
hectares
258.998811034 ha
ares
25,899.8811034 a
square meters
2,589,988.11034 m²
square centimeters
25,899,881,103.4 cm²
square millimeters
2,589,988,110,340 mm²
square micrometers
2.58998811034 × 10¹⁸ µm²

1 sq mi = 2.58998811034 km²

Show the working
  1. 1 sq mi = 2.58998811034 km²
  2. 1 × 2.58998811034 = 2.58998811034 km²

How to convert square miles to square kilometers

1 sq mi = 2.58998811034 km², so multiply by 2.58998811034 to go from square miles to square kilometers. Going the other way, 1 km² = 0.386102158542 sq mi.

km² = sq mi × 2.58998811034
sq mi = km² × 0.386102158542

Worked example:

1 sq mi = 2.58998811034 km²
5 × 2.58998811034 = 12.9499405517 km²

Square Miles to square kilometers table

Square MilesSquare Kilometers
1 sq mi2.58998811034 km²
2 sq mi5.17997622067 km²
3 sq mi7.76996433101 km²
4 sq mi10.3599524413 km²
5 sq mi12.9499405517 km²
6 sq mi15.539928662 km²
7 sq mi18.1299167724 km²
8 sq mi20.7199048827 km²
9 sq mi23.309892993 km²
10 sq mi25.8998811034 km²
15 sq mi38.849821655 km²
20 sq mi51.7997622067 km²
25 sq mi64.7497027584 km²
30 sq mi77.6996433101 km²
40 sq mi103.599524413 km²
50 sq mi129.499405517 km²
75 sq mi194.249108275 km²
100 sq mi258.998811034 km²
250 sq mi647.497027584 km²
500 sq mi1,294.99405517 km²
1000 sq mi2,589.98811034 km²

About the units

Square Miles (sq mi)
Square miles, a US customary unit. Definition: NIST Handbook 44 Appendix C (derived from the international mile).
Square Kilometers (km²)
Square kilometers, a metric unit. Definition: BIPM SI Brochure (SI prefixes).

Formula version 0.1.0Reviewed