📐 km² to mi² — Square Kilometer to Square Mile Converter

Convert area units — square meters, square feet, acres, hectares, cents, grounds and more.

1 unit =
From
To
Formula 1 km² = 0.38610217 mi²
UnitNameValue
0.001 km²0.000386102 mi²
0.01 km²0.00386102 mi²
0.1 km²0.0386102 mi²
1 km²0.386102 mi²
5 km²1.93051 mi²
10 km²3.86102 mi²
50 km²19.3051 mi²
100 km²38.6102 mi²
1000 km²386.102 mi²
Last updated: March 2026

Square Kilometer to Square Mile Conversion Table

Common square kilometer values converted to square mile — factor: 1 km² = 0.3861 mi²

Square Kilometer (km²)Square Mile (mi²)Context
0.001 km²0.0003861 mi²Large park
0.01 km²0.003861 mi²Airport
0.1 km²0.03861 mi²Town center
0.5 km²0.1931 mi²Small suburb
1 km²0.3861 mi²Suburb
5 km²1.931 mi²Small town
10 km²3.861 mi²Large town
50 km²19.31 mi²Small city
100 km²38.61 mi²City
500 km²193.1 mi²Large city
1,000 km²386.1 mi²Metro area
5,000 km²1,931 mi²Small country
1e+04 km²3,861 mi²Small country
5e+04 km²1.931e+04 mi²Large country
1e+05 km²3.861e+04 mi²Large country

About Square Kilometer to Square Mile Conversion

Converting square kilometer to square mile is common in real estate, agriculture, surveying, and construction. Property listings, land records, and planning documents often use different area units depending on the country or industry — making accurate conversion essential for cross-border transactions and international comparisons.

As a practical reference: 5 km² = 1.931 square mile and 10 km² = 3.861 square mile. For larger land areas, 100 km² = 38.61 square mile — a common benchmark for farm and estate valuations. The reverse: 1 mi² = 2.59 km².

All conversions use the internationally recognized factor of exactly 1 km² = 0.3861 mi². Calculations are performed in IEEE 754 double-precision floating point, giving accuracy to at least 8 significant figures — more than sufficient for any practical application.

Quick Answer

Formula: Square Mile = Square Kilometer × 0.38610217

Multiply any square kilometer value by 0.38610217 to get square mile. One square kilometer equals 0.38610217 mi².

Reverse: Square Kilometer = Square Mile × 2.589988

Worked Examples

One square kilometer
1 km² × 0.38610217 = 0.38610217 mi²
1 km² = 0.3861 mi².
One square mile
2.58999 km² × 0.38610217 = 1.0000008 mi²
2.58999 km² = 1 mi².
100 km²
100 km² × 0.38610217 = 38.610217 mi²
100 km² = 38.61 mi².
Contiguous US
9.861e+06 km² × 0.38610217 = 3.807e+06 mi²
9,861,000 km² = 3,806,000 mi².

Mental Math Tricks

× 0.386

km² × 0.386 = mi². Round to × 0.4 for rough estimates (3.6% high).

2.59 km² = 1 mi²

Memorize: 2.59 km² per square mile.

Reverse

mi² × 2.59 = km².

Who Uses This Conversion?

Cartographer

Measures and labels geographic features like lakes, forests, and countries in km².

Geographer

Analyzes land use, population density, and territory size in square kilometers.

Government Official

Reports national territory, protected area, and urban footprint in km².

Urban Planner

Assesses metropolitan area growth and infrastructure needs in km².

Environmental Analyst

Tracks deforestation, desertification, and habitat change in km².

Insurance Actuary

Calculates wildfire, flood, or storm risk exposure over geographic areas in km².

Frequently Asked Questions

About Square Kilometer and Square Mile

Square Kilometer (km²)

The square kilometer is equal to one million square meters, used for measuring large geographic areas such as countries, forests, lakes, and urban regions.

It became the standard measure for national territories and natural features as cartography evolved in the 19th and 20th centuries alongside the metric system.

Interesting fact: The world's smallest country, Vatican City, covers just 0.44 km². Russia, the largest, spans about 17.1 million km².

Square Mile (mi²)

The square mile is an Imperial unit equal to 640 acres or about 2.59 km². It is used for measuring large territories, cities, and geographic features in the US and UK.

US census data reports city and county areas in square miles. The term 'square mile' also colloquially refers to the City of London financial district.

Interesting fact: Manhattan island in New York City covers about 23 square miles. The entire US is approximately 3.8 million square miles.