⬜ mi² to km² — Square Mile to Square Kilometer Converter

Convert area units — square meters, acres, hectares, square feet, square kilometers.

1 unit =
From
To
Formula 1 mi² = 2.589988 km²
UnitNameValue
Square Meter 2589990
km² Square Kilometer 2.58999
ha Hectare 258.999
ac Acre 639.9999
ft² Square Foot 27878432
yd² Square Yard 3097603.6
Last updated: March 2026

Square Mile to Square Kilometer Conversion Table

Common square mile values converted to square kilometer — factor: 1 mi² = 2.59 km²

Square Mile (mi²)Square Kilometer (km²)Context
0.1 mi²0.259 km²Suburb
0.25 mi²0.6475 km²Small town
0.5 mi²1.295 km²Small town
1 mi²2.59 km²Small town
2 mi²5.18 km²Small town
5 mi²12.95 km²Medium town
10 mi²25.9 km²Small city
20 mi²51.8 km²Small city
25 mi²64.75 km²Large city
50 mi²129.5 km²Large city
100 mi²259 km²Metro area
250 mi²647.5 km²County
500 mi²1,295 km²County
1,000 mi²2,590 km²Small state
5,000 mi²1.295e+04 km²Large state

About Square Mile to Square Kilometer Conversion

Converting square mile to square kilometer 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 mi² = 12.95 square kilometer and 10 mi² = 25.9 square kilometer. For larger land areas, 100 mi² = 259 square kilometer — a common benchmark for farm and estate valuations. The reverse: 1 km² = 0.3861 mi².

All conversions use the internationally recognized factor of exactly 1 mi² = 2.59 km². 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 Kilometer = Square Mile × 2.589988

Multiply any square mile value by 2.589988 to get square kilometer. One square mile equals 2.589988 km².

Reverse: Square Mile = Square Kilometer × 0.38610217

Worked Examples

One square mile
1 mi² × 2.589988 = 2.589988 km²
1 mi² = 2.58999 km².
One square kilometer
0.3861 mi² × 2.589988 = 0.99999437 km²
0.3861 mi² = 1 km².
10 square miles
10 mi² × 2.589988 = 25.89988 km²
10 mi² = 25.9 km².
contiguous US
3806 mi² × 2.589988 = 9857.4943 km²
~3,806 thousand mi² = ~9.86 million km².

Mental Math Tricks

× 2.59

mi² × 2.59 = km². Round to × 2.6 for quick estimates.

1 mi² ≈ 2.6 km²

One square mile is about 2.6 square kilometers.

Reverse

km² × 0.386 = mi².

Who Uses This Conversion?

Geographer

Measures and compares geographic region sizes in square miles.

US Census Analyst

Reports population density in people per square mile.

Wildfire Manager

Tracks fire perimeter and burned area in square miles.

Real Estate Developer

Assesses large land parcels in square miles for master-planned communities.

Military Planner

Defines operational theater and patrol areas in square miles.

Journalist

Describes scale of disasters and developments in square miles for US audiences.

Frequently Asked Questions

About Square Mile and Square Kilometer

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.

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.