Square Miles to km2 Converter
1 square mile = 2.58999 km2. Used for US state and county areas.
Formula:1 mi2 = 2.58999 km2
⇄ Switch to Square Km To Square MilesSq. mile to Sq. kilometer — common values
1 mi²2.589988 km²
10 mi²25.89988 km²
100 mi²258.9988 km²
1,000 mi²2,589.988 km²
10,000 mi²25,899.88 km²
100,000 mi²258,998.8 km²
1,000,000 mi²2,589,988 km²
How to convert Square Miles To Square Km
To convert square miles to square km, use the formula: 1 mi2 = 2.58999 km2. Enter any value in the input field above and the result appears instantly. Click the ⇄ button or use the “Switch to Square Km To Square Miles” link to reverse the conversion.
All conversions use precise mathematical constants validated against international SI standards (NIST and ISO 80000) and are accurate to 8 significant figures.
Frequently Asked Questions
What is the formula to convert Square Miles To Square Km?
1 mi2 = 2.58999 km2. 1 square mile = 2.58999 km2. Used for US state and county areas.
Is this converter free?
Yes — completely free, no registration required. Works instantly in your browser.
How do I convert Square Km To Square Miles?
Use the Square Km To Square Miles converter or click the ⇄ switch button above.
More Area conversions
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The full converter supports all unit combinations