How to convert square miles to square kilometers
km² = mi² × 2.58998811Multiply the value in square miles by 2.58998811. To go the other way, multiply by 0.3861021585 (or divide by 2.58998811).
A square mile is larger than a square kilometer: one square mile contains 2.58998811 square kilometers.
Worked examples
- 1 square mile1 mi² × 2.58998811 = 2.58998811 km²
- 5 square miles5 mi² × 2.58998811 = 12.94994055 km²
- 10 square miles10 mi² × 2.58998811 = 25.8998811 km²
- 20 square miles20 mi² × 2.58998811 = 51.79976221 km²
- 100 square miles100 mi² × 2.58998811 = 258.998811 km²
Square miles to square kilometers conversion table
Values are calculated by the conversion engine and rounded to 8 significant figures.
| Square miles (mi²) | Square kilometers (km²) |
|---|---|
| 0.1 mi² | 0.25899881 km² |
| 0.25 mi² | 0.64749703 km² |
| 0.5 mi² | 1.2949941 km² |
| 1 mi² | 2.5899881 km² |
| 2 mi² | 5.1799762 km² |
| 3 mi² | 7.7699643 km² |
| 4 mi² | 10.359952 km² |
| 5 mi² | 12.949941 km² |
| 6 mi² | 15.539929 km² |
| 7 mi² | 18.129917 km² |
| 8 mi² | 20.719905 km² |
| 9 mi² | 23.309893 km² |
| 10 mi² | 25.899881 km² |
| Square miles (mi²) | Square kilometers (km²) |
|---|---|
| 12 mi² | 31.079857 km² |
| 15 mi² | 38.849822 km² |
| 20 mi² | 51.799762 km² |
| 25 mi² | 64.749703 km² |
| 30 mi² | 77.699643 km² |
| 40 mi² | 103.59952 km² |
| 50 mi² | 129.49941 km² |
| 75 mi² | 194.24911 km² |
| 100 mi² | 258.99881 km² |
| 250 mi² | 647.49703 km² |
| 500 mi² | 1,294.9941 km² |
| 1,000 mi² | 2,589.9881 km² |
About the units
Square mile (mi²)
640 acres. Used for US counties, states and wildfire extents. One square mile equals 2,589,988.11 square meters (m²).
Square kilometer (km²)
One million square metres or 100 hectares; used for city, lake and country areas. One square kilometer equals 1,000,000 square meters (m²).
Frequently asked questions
How many square kilometers are in one square mile?
There are 2.58998811 square kilometers in one square mile, and this value is exact by definition.
How do I convert square miles to square kilometers?
Multiply the number of square miles by 2.58998811. For example, 10 mi² × 2.58998811 = 25.8998811 km².
How many square miles are in one square kilometer?
One square kilometer equals 0.3861021585 square miles. That is the reverse factor, 1 ÷ 2.58998811.
What is 10 square miles in square kilometers?
10 mi² = 25.8998811 km².
Is this mi² to km² converter accurate?
Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.