Square Miles to Square Kilometers Converter (sq mi to sq km)

Convert square miles to square kilometers (sq mi to sq km) instantly. Learn the formula, see US state and city area comparisons, and understand how American and metric land area units relate.

🗺️ SQUARE MILES (mi²)

mi²

AREA IN SQUARE KILOMETERS

2.59 km²

HECTARES

259 ha

ACRES

640 ac

SQUARE METERS

2,589,988 m²

FORMULA

1 × 2.59

Square Miles to Square Kilometers — Quick Reference

mi²	km²	Acres	Approx. Size
0.01 mi²	0.026 km²	6.4 ac	City block
0.1 mi²	0.259 km²	64 ac	Small park
0.5 mi²	1.295 km²	320 ac	Large park
1 mi²	2.59 km²	640 ac	Large park
2 mi²	5.18 km²	1,280 ac	Small town
5 mi²	12.95 km²	3,200 ac	Small town
10 mi²	25.9 km²	6,400 ac	Small city
25 mi²	64.75 km²	16,000 ac	Small city
50 mi²	129.499 km²	32,000 ac	Large city
100 mi²	258.999 km²	64,000 ac	Large city
500 mi²	1,294.994 km²	320,000 ac	US county
1,000 mi²	2,589.988 km²	640,000 ac	Rhode Island area
3,000 mi²	7,769.964 km²	1,920,000 ac	Large county
10,000 mi²	25,899.88 km²	6,400,000 ac	US state

How to Convert Square Miles to Square Kilometers

To convert square miles to square kilometers, multiply the area by 2.589988:

square kilometers = square miles × 2.589988

Example: 10 square miles
= 10 × 2.589988 = 25.90 km²

Example: Manhattan (22.82 sq mi)
= 22.82 × 2.589988 = 59.10 km²

The conversion factor comes from the relationship between miles and kilometers. Since 1 mile = 1.609344 kilometers (by international agreement), 1 square mile = 1.609344 × 1.609344 = 2.589988 square kilometers. This is an exact value — not a rounded approximation.

Square Miles to Square Kilometers — Conversion Table

Square Miles	Square Kilometers	Acres	Approx. Size
0.1 sq mi	0.259 km²	64 ac	Small neighborhood
0.5 sq mi	1.295 km²	320 ac	Large park
1 sq mi	2.590 km²	640 ac	1 section of land
5 sq mi	12.950 km²	3,200 ac	Small town
10 sq mi	25.900 km²	6,400 ac	Small city
22.82 sq mi	59.10 km²	14,605 ac	Manhattan, NYC
36 sq mi	93.24 km²	23,040 ac	1 township (PLSS)
68.34 sq mi	176.99 km²	43,738 ac	Washington, D.C.
302.6 sq mi	783.8 km²	193,664 ac	New York City (5 boroughs)
640 sq mi	1,657.6 km²	409,600 ac	Typical large US county
1,214 sq mi	3,144 km²	776,960 ac	Rhode Island (smallest state)
10,931 sq mi	28,311 km²	6,995,840 ac	Massachusetts
268,596 sq mi	695,662 km²	171,901,440 ac	Texas
663,268 sq mi	1,717,854 km²	424,491,520 ac	Alaska (largest state)

What Is a Square Mile?

A square mile (symbol: mi² or sq mi) is a US customary and imperial unit of area equal to the area of a square with sides of 1 mile (5,280 feet) in length.

1 square mile = 640 acres
1 square mile = 2.589988 square kilometers
1 square mile = 27,878,400 square feet
1 square mile = 3,097,600 square yards
1 square mile = 1 section in the US Public Land Survey System (PLSS)
36 square miles = 1 township (6 miles × 6 miles)

Square miles are the standard unit for measuring large land areas in the United States. US Census data, state areas, county sizes, city limits, and federal land measurements all use square miles. When Americans read "Texas is 268,596 square miles," they're using this unit.

What Is a Square Kilometer?

A square kilometer (symbol: km² or sq km) is a metric unit of area equal to the area of a square with sides of 1 kilometer (1,000 meters) in length. It is a multiple of the square meter, which is the SI derived unit of area.

1 square kilometer = 0.386102 square miles
1 square kilometer = 100 hectares
1 square kilometer = 1,000,000 square meters
1 square kilometer = 247.105 acres

Square kilometers are used internationally for reporting country areas, geographic regions, and large-scale land measurements. The United Nations, World Bank, and CIA World Factbook all report country areas in square kilometers.

US National Parks — Area in Square Miles and Square Kilometers

National Parks are among the most recognizable large areas Americans know. Here's how some of the most popular ones compare:

National Park	Square Miles	Square Kilometers	State
Yellowstone	3,471 sq mi	8,991 km²	WY / MT / ID
Grand Canyon	1,904 sq mi	4,931 km²	Arizona
Yosemite	1,187 sq mi	3,074 km²	California
Glacier	1,584 sq mi	4,101 km²	Montana
Great Smoky Mountains	816 sq mi	2,114 km²	TN / NC
Zion	229 sq mi	593 km²	Utah
Acadia	76 sq mi	198 km²	Maine

When Americans Need to Convert Square Miles to Square Kilometers

International comparisons — News articles comparing US areas to other countries often need conversion. "Is Texas bigger than France?" Texas = 268,596 mi² (695,662 km²); France = 248,573 mi² (643,801 km²). Yes.
Geography and education — US school geography textbooks use square miles, but international curricula and Wikipedia use square kilometers.
Environmental and scientific research — Research papers, UN reports, and environmental studies report land use, deforestation, and habitat areas in square kilometers.
Travel and tourism — International travel guides describe country and city sizes in km². Knowing that New York City (302.6 mi²) = 783.8 km² helps Americans relate to international city sizes.
Real estate and land management — Large ranch and agricultural land in the western US is sometimes sold in sections (1 sq mi = 640 acres = 2.59 km²).
Military and government — NATO and international defense agreements use metric units for area calculations.

US Land Area — Key Facts

Total US land area: 3,531,905 sq mi (9,147,593 km²) — 3rd or 4th largest country by area, depending on how coastal/territorial waters are counted.
Largest state: Alaska — 663,268 sq mi (1,717,854 km²)
Smallest state: Rhode Island — 1,214 sq mi (3,144 km²)
1 section (PLSS): 1 sq mi = 640 acres — the basic land survey unit used across 30 US states
1 township: 36 sq mi (6 × 6 miles) — still used in property descriptions in Midwest and Western states

Related Area Units

Unit	In Square Miles	In Square Kilometers
1 acre	0.0015625 mi²	0.00405 km²
1 square foot	3.587 × 10⁻⁸ mi²	9.290 × 10⁻⁸ km²
1 hectare	0.003861 mi²	0.01 km²
1 square mile	1 mi²	2.589988 km²
1 square kilometer	0.386102 mi²	1 km²
1 township (PLSS)	36 mi²	93.24 km²