By Tim King · Updated 19 September 2026

Square km to Square Miles Converter

Square Kilometres to Square Miles and Back, Exact Factor Explained

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square miles to square kilometres table ↓

square kilometres to square miles formula

mi² = km² ÷ 2.589988110336

1 square kilometre = 0.3861021585 square miles, so multiply square kilometres by 0.3861021585. Going the other way, 1 square mile = 2.589988111 square kilometres.

square kilometres to square miles table

square kilometres (km²)	square miles (mi²)
1	0.386102
2	0.772204
5	1.93051
10	3.86102
20	7.72204
25	9.65255
50	19.3051
100	38.6102
200	77.2204
250	96.5255
500	193.051
1,000	386.102
1,572	606.953
2,000	772.204
5,000	1,930.51
10,000	3,861.02
20,000	7,722.04
50,000	19,305.1
100,000	38,610.2
243,610	94,058.3
500,000	193,051
1,000,000	386,102

How many square miles in square kilometres?

1 km² = 0.386102 mi². There are 0.386102 square miles in 1 square kilometres.

10 km² = 3.86102 mi². There are 3.86102 square miles in 10 square kilometres.

100 km² = 38.6102 mi². There are 38.6102 square miles in 100 square kilometres.

1,000 km² = 386.102 mi². There are 386.102 square miles in 1,000 square kilometres.

10,000 km² = 3,861.02 mi². There are 3,861.02 square miles in 10,000 square kilometres.

square miles to square kilometres formula

km² = mi² × 2.589988110336

1 square mile = 2.589988111 square kilometres, so multiply square miles by 2.589988111, or divide by 0.3861021585.

square miles to square kilometres table

square miles (mi²)	square kilometres (km²)
1	2.58999
2	5.17998
5	12.9499
10	25.8999
20	51.7998
25	64.7497
50	129.499
100	258.999
200	517.998
250	647.497
500	1,294.99
1,000	2,589.99
1,500	3,884.98
2,000	5,179.98
5,000	12,949.9
10,000	25,899.9
20,000	51,799.8
50,000	129,499
100,000	258,999
268,596	695,660
500,000	1,294,994
1,000,000	2,589,988

How many square kilometres in square miles?

1 mi² = 2.58999 km². There are 2.58999 square kilometres in 1 square miles.

10 mi² = 25.8999 km². There are 25.8999 square kilometres in 10 square miles.

100 mi² = 258.999 km². There are 258.999 square kilometres in 100 square miles.

1,000 mi² = 2,589.99 km². There are 2,589.99 square kilometres in 1,000 square miles.

10,000 mi² = 25,899.9 km². There are 25,899.9 square kilometres in 10,000 square miles.

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How the Square Km To Square Miles works

This square km to square miles converter squares the length factor. Type an area in square kilometres and get square miles as you type. A mile is 1.609344 km, so a square mile is 2.58999 km² and a square kilometre is 0.386102 square miles — a bit over a third. The table covers cities, counties and countries, from a small town to a million square kilometres. Press the swap button to go the other way.

Square km to square miles: square the length factor

A kilometre is 0.621371 miles; an area is two lengths, so a square kilometre is 0.621371² = 0.386102 square miles. Through the exact definition: a mile is 1,609.344 m, a square mile is 2,589,988.11 m², and a square kilometre is 1,000,000 ÷ 2,589,988.11 = 0.3861 of one. Using 0.62 unsquared is the common mistake; it makes an area 60% too large.

Worked example: Greater London, 1,572 km²

1,572 × 0.386102 = 607 square miles. New York City is 784 km², 303 sq mi; Paris inside the périphérique is 105 km², 41 sq mi; Los Angeles is 1,302 km², 503 sq mi. City comparisons are dominated by where the boundary is drawn, and both the metric and the imperial figure inherit that.

Worked example: the United Kingdom, 243,610 km²

243,610 × 0.386102 = 94,058 square miles. France is 551,695 km², or 213,011 sq mi; Texas is 695,662 km², 268,596 sq mi; the contiguous United States is about 8.08 million km², 3.12 million sq mi. At this scale the figures are rounded anyway, and the quarter-percent difference between 0.386 and 0.3861 disappears.

Population density

Density in people per square kilometre converts to people per square mile by multiplying by 2.59, not by 0.386 — the "per" inverts the factor. London's 5,700 per km² is 14,700 per square mile. Rainfall, yield and cost per unit area invert the same way.

Hectares and acres

A square kilometre is 100 hectares or 247.1 acres; a square mile is 640 acres or 259 hectares. For farms and parks the hectares-to-acres page is the useful one; this page is for anything mapped rather than fenced.

Rule of thumb

Multiply by 0.4 and take off a little: 500 km² is about 200 − 7 = 193 sq mi (exact: 193.05). Going the other way, multiply square miles by 2.6. The 0.4 estimate is 3.6% high, which is fine for a headline and not for a land registry, so use the converter for anything that will be written down.

Worked example: Texas, 268,596 square miles

268,596 × 2.589988 = 695,662 km². Alaska is 665,384 sq mi, 1,723,337 km²; Rhode Island is 1,545 sq mi, 4,001 km². The contiguous United States is 3.12 million square miles, 8.08 million km², and the whole country 3.8 million square miles, 9.83 million km².

Worked example: Yellowstone, 3,472 square miles

3,472 × 2.589988 = 8,992 km². American parks and counties are quoted in square miles; the same figure appears as 8,983 km² in some sources because it was measured in acres — 2,221,766 of them — and rounded twice. A section of surveyed land is exactly one square mile, 640 acres, 259 hectares.

Square kilometre to square miles formula and table

The formula on this page is mi² = km² ÷ 2.589988110336, applied exactly before rounding for display.

How many square miles in 1 square kilometre? 1 km² is 0.3861 mi². Likewise 10 km² is 3.861 mi², 100 km² is 38.61 mi², 1,000 km² is 386.1 mi².

Square kilometre to square mile conversion table

Square kilometres (km²)	Square miles (mi²)
1	0.3861
2	0.7722
5	1.9305
10	3.861
20	7.722
25	9.6526
50	19.31
100	38.61
200	77.22
250	96.53
500	193.05
1,000	386.1
1,572	606.95
2,000	772.2
5,000	1,931
10,000	3,861
20,000	7,722
50,000	19,305
100,000	38,610
243,610	94,058
500,000	193,051
1,000,000	386,102

FAQ

How many square miles are in a square kilometre?

0.386102 square miles. A square mile is 2.589988 km², so a square kilometre is 1 ÷ 2.59 of one. Roughly, five square kilometres make two square miles.

How do I convert km² to mi² in my head?

Multiply by 0.4 and subtract about 3% of the result. 1,000 km² is 400 minus 14, or 386 square miles. For the reverse, multiply by 2.6.

How many square kilometres is a square mile?

2.589988 km², exactly 2.589988110336, because a mile is 1.609344 km and that number squared. A square mile is also 640 acres or 259 hectares. A square kilometre is 100 hectares or 247 acres.

How many acres in a square kilometre?

247.105 acres, or exactly 100 hectares. A square mile is 640 acres. Land within a single farm is quoted in hectares or acres; regions and countries in square kilometres or square miles.

How many square kilometres are in a square mile?

2.589988 km², exactly 2.589988110336. A mile is 1.609344 km and the factor is that number squared. A square kilometre is 0.3861 square miles, a little over a third.