This converter turns square kilometers into square miles instantly, using the exact factor 1 square kilometer = 0.3861021585 square miles. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
One million square metres — the unit for cities, lakes and districts. The unit for counties, national parks and weather systems in the US and UK.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
square kilometers- The amount you are converting, measured in square kilometers
0.3861021585- The exact number of square miles in one square kilometer
square miles- The converted result
How it works, step by step
- Enter the number of square kilometers you want to convert.
- The value is multiplied by 0.3861021585, the exact conversion factor.
- The result is displayed in square miles, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 square kilometers
Multiply 5 by 0.38610216. That gives 1.9305 square miles. A quick sanity check: one square kilometer is smaller than one square mile, so the number should get smaller — and it does.
Converting 72 square kilometers
72 × 0.38610216 = 27.7994 square miles. Working backwards, 27.7994 ÷ 0.38610216 returns 72 square kilometers, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many square miles are in one square kilometer?
Exactly 0.3861021585. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert square kilometers to square miles?
Square Miles = square kilometers × 0.3861021585. To reverse it, divide instead: square kilometers = square miles ÷ 0.3861021585, which is the same as multiplying by 2.58998811.
Is the square kilometer bigger than the square mile?
No. One square kilometer is only 0.386102 of a square mile, so the square mile is the larger unit.
Why does my answer differ slightly from other square-kilometers to square-miles converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a square kilometer?
One million square metres — the unit for cities, lakes and districts.
What is a square mile?
The unit for counties, national parks and weather systems in the US and UK.
Square Kilometers to square miles reference table
| Square Kilometers | Square Miles |
|---|---|
| 0.5 km² | 0.193051 mi² |
| 1 km² | 0.386102 mi² |
| 2 km² | 0.772204 mi² |
| 3 km² | 1.1583 mi² |
| 5 km² | 1.9305 mi² |
| 10 km² | 3.861 mi² |
| 15 km² | 5.7915 mi² |
| 20 km² | 7.722 mi² |
| 25 km² | 9.6526 mi² |
| 50 km² | 19.3051 mi² |
| 75 km² | 28.9577 mi² |
| 100 km² | 38.6102 mi² |
| 250 km² | 96.5255 mi² |
| 500 km² | 193.0511 mi² |
| 1000 km² | 386.1022 mi² |
Exact factor: 1 square kilometer = 0.3861021585 square miles. Values rounded for display.