Area converter
Square Kilometers to Square Miles
Square Kilometers and Square Miles measure the same quantity in different unit systems. The relationship is 1 km² = 0.38610216 mi², which gives 0.38610216 mi² per km². Below you can convert any value, check a worked example and read the full chart.
Formula 1 km² = 0.38610216 mi²
Need the other direction? Square Miles to Square Kilometers.
How to convert Square Kilometers to Square Miles
A square kilometre is one million square metres, used for land and administrative areas. A square mile is 2,589,988.11 square metres, or 640 acres.
To convert Square Kilometers to Square Miles, multiply the value in km² by 0.38610216. For example, 10 km² × 0.38610216 = 3.861022 mi². This works because the ratio between the two units is constant for every value in area.
Worked examples
| km² | mi² |
|---|---|
| 1 km² | 0.38610216 mi² |
| 2.5 km² | 0.9652554 mi² |
| 5 km² | 1.930511 mi² |
| 10 km² | 3.861022 mi² |
| 25 km² | 9.652554 mi² |
| 50 km² | 19.305108 mi² |
| 100 km² | 38.610216 mi² |
Reverse conversion
| mi² | km² |
|---|---|
| 1 mi² | 2.589988 km² |
| 5 mi² | 12.949941 km² |
| 10 mi² | 25.899881 km² |
| 25 mi² | 64.749703 km² |
| 50 mi² | 129.499406 km² |
| 100 mi² | 258.998811 km² |
When this conversion is useful
This is the calculation you need when you are comparing property listings, land size or building materials across measurement systems. Because the factor is fixed, you can use the same number for a single measurement or for a batch: 1,000 km² is 386.102159 mi².
Is the conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Reference: BIPM SI Brochure and NIST SP 811. Last reviewed: 2026-11-01.
km² to mi² conversion chart
The chart lists the most requested values. For a value that is not here, use the converter at the top of the page.
| Square Kilometers (km²) | Square Miles (mi²) |
|---|---|
| 1 km² | 0.38610216 mi² |
| 2 km² | 0.77220432 mi² |
| 3 km² | 1.158306 mi² |
| 4 km² | 1.544409 mi² |
| 5 km² | 1.930511 mi² |
| 6 km² | 2.316613 mi² |
| 7 km² | 2.702715 mi² |
| 8 km² | 3.088817 mi² |
| 9 km² | 3.474919 mi² |
| 10 km² | 3.861022 mi² |
| 11 km² | 4.247124 mi² |
| 12 km² | 4.633226 mi² |
| 13 km² | 5.019328 mi² |
| 14 km² | 5.40543 mi² |
| 15 km² | 5.791532 mi² |
| 16 km² | 6.177635 mi² |
| 17 km² | 6.563737 mi² |
| 18 km² | 6.949839 mi² |
| 19 km² | 7.335941 mi² |
| 20 km² | 7.722043 mi² |
| 21 km² | 8.108145 mi² |
| 22 km² | 8.494247 mi² |
| 23 km² | 8.88035 mi² |
| 24 km² | 9.266452 mi² |
| 25 km² | 9.652554 mi² |
| 26 km² | 10.038656 mi² |
| 27 km² | 10.424758 mi² |
| 28 km² | 10.81086 mi² |
| 29 km² | 11.196963 mi² |
| 30 km² | 11.583065 mi² |
| 31 km² | 11.969167 mi² |
| 32 km² | 12.355269 mi² |
| 33 km² | 12.741371 mi² |
| 34 km² | 13.127473 mi² |
| 35 km² | 13.513576 mi² |
| 36 km² | 13.899678 mi² |
| 37 km² | 14.28578 mi² |
| 38 km² | 14.671882 mi² |
| 39 km² | 15.057984 mi² |
| 40 km² | 15.444086 mi² |
| 41 km² | 15.830189 mi² |
| 42 km² | 16.216291 mi² |
| 43 km² | 16.602393 mi² |
| 44 km² | 16.988495 mi² |
| 45 km² | 17.374597 mi² |
| 46 km² | 17.760699 mi² |
| 47 km² | 18.146801 mi² |
| 48 km² | 18.532904 mi² |
| 49 km² | 18.919006 mi² |
| 50 km² | 19.305108 mi² |
| 60 km² | 23.16613 mi² |
| 70 km² | 27.027151 mi² |
| 80 km² | 30.888173 mi² |
| 90 km² | 34.749194 mi² |
| 100 km² | 38.610216 mi² |
Frequently asked questions
How many Square Miles are in 1 Square Kilometers?
1 km² equals 0.38610216 mi².
How do I convert Square Kilometers to Square Miles?
Multiply the km² value by 0.38610216. Example: 25 km² = 9.652554 mi².
What is 2.5 km² in mi²?
2.5 km² = 0.9652554 mi².
Is the km² to mi² conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Does the calculator work offline?
Yes. The conversion runs in your browser with JavaScript, so it works after the page has loaded, even without a connection.