Square Kilometers to Square Miles
Convert square kilometers to square miles instantly. 1 km² = 0.3861021585 mi². Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert square kilometers to square miles
To convert square kilometers to square miles, divide by 2.5899881103 (multiply by 0.3861021585). The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.
mi² = km² × 0.3861021585
Square Kilometers to Square Miles conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Square Kilometers | Square Miles |
|---|---|
| 1 km² | 0.386102 mi² |
| 2 km² | 0.772204 mi² |
| 3 km² | 1.158306 mi² |
| 5 km² | 1.930511 mi² |
| 10 km² | 3.861022 mi² |
| 20 km² | 7.722043 mi² |
| 25 km² | 9.652554 mi² |
| 50 km² | 19.305108 mi² |
| 100 km² | 38.610216 mi² |
| 500 km² | 193.051079 mi² |
| 1,000 km² | 386.102159 mi² |
What is a square kilometer?
One million square metres. Used for city, park and lake areas.
What is a square mile?
640 acres. Used for counties, states and weather-warning areas.
The formula
mi² = km² × 0.3861021585
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Square Kilometers to Square Miles
- Type the number of square kilometers you want to convert.
- Read the result in square miles straight away — there is no button to press.
- Check the table below for the values that come up most often, or reverse the conversion with the linked square miles to square kilometers page.
Square Kilometers to Square Miles — frequently asked questions
How many square miles are in a square kilometer?
One square kilometer equals 0.3861021585 mi². mi² = km² × 0.3861021585
What is the formula to convert square kilometers to square miles?
The formula is mi² = km² × 0.3861021585. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert square miles back to square kilometers?
Divide instead of multiplying: one square mile is 2.5899881103 km². The reverse converter is linked in the related tools list.
Is this conversion exact?
Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.
Is this square kilometers to square miles free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
What people search for
This page answers each of these searches. They are the exact phrases visitors use to find the square kilometers to square miles.
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About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 15, 2026 · Calculation runs client-side · No data collected · Report an error