square kilometer to square mile
Convert square kilometer (km²) to square mile (mi²). Use an editable area converter, conversion formula, and reference table.
1 km² = 0.3861021585 mi²
Conversion formula
One square kilometer equals 0.3861021585 square mile. Multiply your value in square kilometer by this factor to get square mile. For the reverse conversion, divide by the same factor.
Worked example
To convert 5 square kilometer:5 × 0.3861021585 = 1.930510793 mi²
Conversion table
| square kilometer (km²) | square mile (mi²) |
|---|---|
| 0.01 | 0.003861021585 |
| 0.1 | 0.03861021585 |
| 1 | 0.3861021585 |
| 2 | 0.7722043171 |
| 5 | 1.930510793 |
| 10 | 3.861021585 |
| 25 | 9.652553964 |
| 50 | 19.30510793 |
| 100 | 38.61021585 |
| 1000 | 386.1021585 |
About these measurements
Area measures a surface in two dimensions.
The base reference used here is the square meter. One square kilometer is 1,000,000 base units; one square mile is 2,589,988.11 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 km² to mi²?
Multiply the quantity in km² by 0.3861021585. You can also type the value into the converter above.
Can I reverse the conversion?
Yes. Use the swap button or open the square mile to square kilometer 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.
