Square Miles to Square Kilometers Converter
1 square mile ≈ 2.58998811 square kilometers
1 square mile equals 2.58999 square kilometers
How to convert square miles to square kilometers
Area factors are squared length factors: 1 ft² = (0.3048 m)². The acre here uses international feet; historic US survey acres differ slightly.
km² = mi² × 2.58998811One square mile is 2.58998811 square kilometers, so a single multiplication converts any value.
25.8999 km² ≈ 10 × 2.58998811Square miles to square kilometers conversion table
Common values in square miles, converted to square kilometers.
| Square miles (mi²) | Square kilometers (km²) |
|---|---|
| 1 | 2.5899881 |
| 2 | 5.1799762 |
| 3 | 7.7699643 |
| 4 | 10.359952 |
| 5 | 12.949941 |
| 10 | 25.899881 |
| 20 | 51.799762 |
| 25 | 64.749703 |
| 50 | 129.49941 |
| 100 | 258.99881 |
| 250 | 647.49703 |
| 500 | 1,294.9941 |
| 1,000 | 2,589.9881 |
About these units
square milemi²
Exactly 640 acres. Used for county and country areas.
square kilometerkm²
One million square metres. Used for land area and geographic regions.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.