Square miles to Square kilometers Converter
Convert square miles to square kilometers. The formula used here is 1 square mile = 2.58998811034 square kilometers. The formula is km² = mi² × 2.58998811034; 1 mi² is 2.59 km².
A US customary and imperial area unit for regions and large land parcels.
A metric area unit used for cities, regions, and large parcels.
Start with your value in square miles, then apply the formula below. It stays visible so you can catch rounding mistakes instead of just copying the output.
For property and construction decisions, carry the converted area with the source unit, rounding rule, and any assumptions about measured boundaries.
Area conversions square the underlying length scale, so small changes in length can become larger changes in area for large rooms or parcels. This page displays converted values with up to 4 decimal places by default.
| Square miles | Square kilometers |
|---|---|
| 1 mi² | 2.59 km² |
| 10 mi² | 25.8999 km² |
| 100 mi² | 258.9988 km² |
Useful for real-estate, land, and property records. Use the same formula with your exact input if the measurement needs to be documented.
Useful for flooring, paint, and construction estimates. Use the same formula with your exact input if the measurement needs to be documented.
Useful for mapping, agriculture, and site planning. Use the same formula with your exact input if the measurement needs to be documented.
How do I convert square miles to square kilometers?
Enter the value in square miles and apply km² = mi² × 2.58998811034. Round the square kilometers result after the conversion, not before.
What is 1 square mile in square kilometers?
1 mi² equals 2.59 km² with the current rounding setting. Keep more decimal places when the result feeds another calculation.
What is 10 mi² in km²?
10 mi² is 25.8999 km². It appears in the lookup table so you can compare it with nearby amounts.
Can I convert square kilometers back to square miles?
Yes. Use the reverse Square kilometers to Square miles converter if you need to go the other direction.
How accurate is this square miles to square kilometers conversion?
The calculator runs the formula in your browser and rounds results to 4 decimal places by default. Area conversions square the underlying length scale, so small changes in length can become larger changes in area for large rooms or parcels.