square mile to square kilometer
Convert square mile (mi²) to square kilometer (km²). Use an editable area converter, conversion formula, and reference table.
1 mi² = 2.58998811 km²
Conversion formula
One square mile equals 2.58998811 square kilometer. Multiply your value in square mile by this factor to get square kilometer. For the reverse conversion, divide by the same factor.
Worked example
To convert 5 square mile:5 × 2.58998811 = 12.94994055 km²
Conversion table
| square mile (mi²) | square kilometer (km²) |
|---|---|
| 0.01 | 0.0258998811 |
| 0.1 | 0.258998811 |
| 1 | 2.58998811 |
| 2 | 5.179976221 |
| 5 | 12.94994055 |
| 10 | 25.8998811 |
| 25 | 64.74970276 |
| 50 | 129.4994055 |
| 100 | 258.998811 |
| 1000 | 2,589.98811 |
About these measurements
Area measures a surface in two dimensions.
The base reference used here is the square meter. One square mile is 2,589,988.11 base units; one square kilometer is 1,000,000 base units.
Important distinctions
Square a length factor to convert an area. Units with equal factors can have different conventional uses.
Precision
The converter uses stored conversion factors and floating-point arithmetic. Results display up to ten significant digits, switching to scientific notation for very small or large values. Keep the precision of your original measurement when reporting results.
Common questions
How do I convert mi² to km²?
Multiply the quantity in mi² by 2.58998811. You can also type the value into the converter above.
Can I reverse the conversion?
Yes. Use the swap button or open the square kilometer to square mile converter.
Reference
NIST Guide to the SI — conversion factors and prefix conventions. SI prefixes scale units by powers of ten; the dimension-specific notes above describe the assumptions used on this page.
