1 mi² = 2.58999 km² (square mile → square kilometer)
1 mi² = 2.58999 km²
1 square mile equals 2.58999 square kilometers. To convert square miles to square kilometers, multiply the square mile value by 2.58999. For quick reference: 1 mi² = 2.58999 km², 5 mi² = 12.9499 km², 10 mi² = 25.8999 km², 100 mi² = 258.999 km².
Square kilometers = Square miles × 2.58999Square miles to square kilometers multiplies by 2.589988110336 (exact). Alaska's 665,384 sq mi is 1.72 million km²; a 50 sq mi county is 129.5 km². Used constantly when US geographic data feeds international comparisons. A useful anchor: 1 sq mi ≈ 2.6 km², so US areas roughly two-and-a-half-times themselves into km² — anyone dividing by 2.6 instead of multiplying will be off by a factor of nearly 7.
Start with your value in square miles.
Multiply the square mile value by 2.58999. This is the exact conversion factor from square miles to square kilometers.
The product is your value in square kilometers. For example, 5 mi² × 2.58999 = 12.9499 km².
The exact factor from square miles to square kilometers is 2.58999.
Square kilometers = Square miles × 2.58999
Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.
| Square miles (mi²) | Square kilometers (km²) |
|---|---|
| 0.1 mi² | 0.259 km² |
| 0.25 mi² | 0.6475 km² |
| 0.5 mi² | 1.295 km² |
| 1 mi² | 2.59 km² |
| 2 mi² | 5.18 km² |
| 3 mi² | 7.77 km² |
| 4 mi² | 10.36 km² |
| 5 mi² | 12.95 km² |
| 6 mi² | 15.54 km² |
| 7 mi² | 18.13 km² |
| 8 mi² | 20.72 km² |
| 9 mi² | 23.31 km² |
| 10 mi² | 25.9 km² |
| 12 mi² | 31.08 km² |
| 15 mi² | 38.85 km² |
| 20 mi² | 51.8 km² |
| 25 mi² | 64.75 km² |
| 30 mi² | 77.7 km² |
| 40 mi² | 103.6 km² |
| 50 mi² | 129.5 km² |
| 60 mi² | 155.4 km² |
| 70 mi² | 181.3 km² |
| 75 mi² | 194.25 km² |
| 80 mi² | 207.2 km² |
| 90 mi² | 233.1 km² |
| 100 mi² | 259 km² |
| 120 mi² | 310.8 km² |
| 150 mi² | 388.5 km² |
| 200 mi² | 518 km² |
| 250 mi² | 647.5 km² |
| 300 mi² | 777 km² |
| 400 mi² | 1036 km² |
| 500 mi² | 1295 km² |
| 600 mi² | 1554 km² |
| 750 mi² | 1942.5 km² |
| 800 mi² | 2072 km² |
| 1000 mi² | 2590 km² |
| 1200 mi² | 3108 km² |
| 1500 mi² | 3885 km² |
| 2000 mi² | 5180 km² |
| 2500 mi² | 6475 km² |
| 3000 mi² | 7770 km² |
| 4000 mi² | 10360 km² |
| 5000 mi² | 12950 km² |
| 7500 mi² | 19425 km² |
| 10000 mi² | 25900 km² |
| 20000 mi² | 51800 km² |
| 50000 mi² | 129499 km² |
| 100000 mi² | 258999 km² |
| 1000000 mi² | 2589988 km² |
A US survey 'section' is exactly 1 square mile (640 acres). Los Angeles covers about 469 sq mi. In square kilometers, that gives you: 1 mi² = 2.58999 km², 10 mi² = 25.8999 km², 100 mi² = 258.999 km².
The square mile is the imperial unit for large land areas, standard in US geography and census data. One square mile is exactly 2.589988110336 km² (1.609344 km squared), or 640 acres — the basis of the US Public Land Survey System's square-mile 'sections'. Los Angeles covers about 469 square miles.
The square kilometer equals one million square meters — the standard unit for city, region, and country areas in metric countries. Manhattan is about 59 km²; Istanbul is about 5,461 km²; Turkey is about 783,562 km². One km² equals exactly 100 hectares or about 0.386 square miles.