Square Miles to Square Kilometers
Convert square mile to square kilometer instantly — type a value and read the result, with the exact formula shown.
Reviewed by the CalcCafe editorial team · Last updated 1 July 2026 · How we test our tools
Example
1 mi² = 2.589988 km², 5 mi² = 12.94994 km², 10 mi² = 25.89988 km².
Common conversions: square mile to square kilometer
Quick reference for the mi² → km² values you are most likely to need, computed with the exact factor the converter above uses. It includes the specific values people most often look up (50 mi², 62 mi², 29 mi², 22 mi², 11 mi²).
| Square mile (mi²) | Square kilometer (km²) |
|---|
| 1 mi² | 2.59 km² |
| 2 mi² | 5.18 km² |
| 3 mi² | 7.77 km² |
| 5 mi² | 12.9499 km² |
| 10 mi² | 25.8999 km² |
| 11 mi² | 28.4899 km² |
| 15 mi² | 38.8498 km² |
| 20 mi² | 51.7998 km² |
| 22 mi² | 56.9797 km² |
| 25 mi² | 64.7497 km² |
| 29 mi² | 75.1097 km² |
| 30 mi² | 77.6996 km² |
| 40 mi² | 103.5995 km² |
| 50 mi² | 129.4994 km² |
| 60 mi² | 155.3993 km² |
| 62 mi² | 160.5793 km² |
| 70 mi² | 181.2992 km² |
| 75 mi² | 194.2491 km² |
| 80 mi² | 207.199 km² |
| 90 mi² | 233.0989 km² |
| 100 mi² | 258.9988 km² |
| 150 mi² | 388.4982 km² |
| 200 mi² | 517.9976 km² |
| 250 mi² | 647.497 km² |
| 500 mi² | 1,294.99 km² |
| 1,000 mi² | 2,589.99 km² |
Square kilometer to Square mile
| Square kilometer (km²) | Square mile (mi²) |
|---|
| 1 km² | 0.386102 mi² |
| 5 km² | 1.9305 mi² |
| 10 km² | 3.861 mi² |
| 50 km² | 19.3051 mi² |
| 100 km² | 38.6102 mi² |
How it works
Square kilometer = Square mile × 2.589988. Every value is converted through a single square meter base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Converting square miles to square kilometers comes up most often when you're comparing land areas across borders: a US national park, county, or metro region is usually measured in square miles, while the rest of the world reports the same area in square kilometers. It also shows up in geography homework, real-estate and ranch listings, wildfire and flood coverage maps, and any time you read a US news story and want the figure in metric terms you can picture.
The two units sit on opposite sides of the metric/imperial divide. The square mile is an imperial and US customary unit built on the statute mile (5,280 feet), so one square mile is 640 acres. The square kilometer is the SI-derived metric unit, simply a square that is 1,000 metres on each side, equal to 100 hectares. Because a mile is longer than a kilometer, a square mile covers more ground than a square kilometer — by a factor of roughly two and a half.
For mental math, treat the factor as "about 2.6": multiply square miles by 2.6 to get square kilometers, and divide by 2.6 (or multiply by ~0.39) to go back. A handy anchor is that 100 square miles is almost exactly 259 square kilometers. The exact factor is 2.589988 km² per mi².
- Mistake to avoid: never convert area by the linear mile-to-kilometer factor (1.609). Area scales with the square, so the correct factor is 1.609² ≈ 2.59 — using 1.609 understates the answer by about 38%.
Frequently asked questions
How do you convert square mile to square kilometer?
Multiply the number of square miles by 2.589988 to get square kilometers. For example, 1 mi² = 2.589988 km².
What is 1 square mile in square kilometers?
1 square mile equals 2.589988 square kilometers (1 mi² = 2.589988 km²).
How many square miles are in 1 square kilometer?
There are 0.3861022 square miles in 1 square kilometer.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
How many square kilometers are in a square mile?
There are 2.589988 square kilometers in one square mile. For rough estimates you can round to 2.59 or even 2.6.
How do I convert square kilometers back to square miles?
Divide square kilometers by 2.589988, or multiply by 0.3861022. For example, 10 km² equals about 3.861 square miles.
How many square kilometers is 100 square miles?
100 square miles equals 258.9988 square kilometers, which rounds neatly to about 259 km².
How many acres are in a square mile, and how does that relate to square kilometers?
One square mile is exactly 640 acres, and it equals 2.589988 square kilometers. Since a square kilometer is 100 hectares, one square mile is about 258.999 hectares.
Why isn't the conversion factor just 1.609 like miles to kilometers?
Because area is two-dimensional, you square the linear factor: 1.609344² = 2.589988. Using 1.609 directly would give the wrong area, off by about 38 percent.
How big is a square mile compared to a square kilometer?
A square mile is larger — about 2.59 square kilometers. Conversely, a square kilometer is only about 0.386 of a square mile.
What is 5 square miles in square kilometers?
5 square miles equals 12.94994 square kilometers (5 × 2.589988). Rounded, that's roughly 12.95 km².
Is the square mile to square kilometer conversion exact?
Yes, the factor 2.589988 km² per mi² is exact because the international mile is defined exactly as 1,609.344 metres. Displayed results are just rounded for readability.
How do I convert sqm to sqkm?
Divide square meters by 1,000,000 to get square kilometers, because a kilometer is 1,000 meters and 1,000² = 1,000,000. So 250,000 m² is 0.25 km², and 2,500,000 m² is 2.5 km². To go on to square miles, divide the km² figure by 2.589988.
How much is 1 sqkm?
One square kilometer is a square 1,000 meters on each side, so it contains 1,000,000 square meters or 100 hectares. In imperial units it is 1 ÷ 2.589988 = 0.3861 square miles, or about 247.1 acres. A square mile is therefore about two and a half times larger than a square kilometer.
Is 200 ft by 200 ft an acre?
Not quite. A 200 ft by 200 ft plot is 40,000 square feet, while an acre is 43,560 square feet, so it is 40,000 ÷ 43,560 = 0.92 acres. A square acre measures about 208.7 feet on each side. In metric terms, 200 by 200 feet is about 3,716 square meters, or 0.0037 km².
What is 20,000 sq m in acres?
20,000 square meters is about 4.94 acres, since 20,000 × 0.0002471054 = 4.942 acres. It is also exactly 2 hectares or 0.02 km², which is 0.02 ÷ 2.589988 = 0.0077 square miles.
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Sources & references
These tools follow our methodology and provide educational estimates only — verify important figures with a qualified professional.