Square Miles to Square Kilometers converter
Quick reference
About area units
Area units square the length units, which is why the numbers get big fast: one square meter is 10.76 square feet, and a hectare (100m x 100m) is about 2.47 acres. The acre itself is medieval, the area a team of oxen could plow in a day, standardized to 43,560 square feet. Real estate is the main crossing point: US listings quote square feet and acres, most of the world quotes square meters and hectares.
More area conversions
Frequently asked questions
What is the exact formula for Square Miles to Square Kilometers?
Multiply the Square Miles value by 2.58998811. This comes from the exact unit definitions, not a rounded approximation.
Is this conversion exact?
The underlying ratio is exact where a legal definition exists (for example, 1 inch = 25.4 mm exactly). Displayed results are rounded to six decimal places for readability.
Can I convert Square Kilometers back to Square Miles?
Yes. Use the reverse converter linked below, or just swap which field you type into: the live converter recalculates either direction.