Sq Mi to Sq Km Converter — Turn US Land Areas into Metric Instantly
Convert square miles to square kilometers in seconds with our free, browser-based tool. Built for Americans sharing US facts with the world — reports, homework, travel, and international business.
Area Conversion CalculatorThe quick answer for 1 Square Miles — type any value below for the exact result
Square Miles
Square Kilometers
Sq Mi to Sq Km Formula: Multiply by 2.59
Multiply the square-mile value by 2.59 to get square kilometers. One mile equals 1.60934 kilometers, and squaring that ratio yields the area factor of 2.59 — it's that straightforward.
Square Miles and Square Kilometers Explained
Square Miles (mi2)
A square mile (sq mi, mi²) is the area of a square measuring one mile — 5,280 feet — on each side, equal to 640 acres or 2.59 square kilometers. It's the go-to unit for American land: Manhattan runs 22.8 sq mi, all five NYC boroughs total 302.6 sq mi of land, Houston covers roughly 640 sq mi, and Rhode Island's 1,033.8 sq mi makes it the smallest state in the Union.
Where it is used: Square miles are the standard in US Census data, National Park Service statistics, county GIS records, real estate listings, and American news coverage of large land areas.
Origin: The statute mile dates to an English act of 1593 setting it at 5,280 feet; as American federal surveyors gridded the West into six-mile townships, the square mile became the nation's standard unit for big areas.
Square Kilometers (km2)
A square kilometer (sq km, km²) is the metric unit for large areas: a square 1,000 meters — about 0.62 miles — on each side, equal to roughly 247 acres or one million square meters. International geography runs on it: Paris spans 105.4 sq km, Lake Balaton 592 sq km, and Malta 316 sq km — so it's the unit your American numbers need when they cross a border.
Where it is used: Square kilometers are standard in UN and EU databases, scientific journals on land use and ecology, Wikipedia infoboxes, and the statistics offices of nearly every country outside the US.
Origin: The kilometer joined the French metric system in 1795 as 1,000 meters; as metrication spread through the 19th and 20th centuries, its square became the world's default unit for large areas.
Square Miles to Square Kilometers Conversion Table
| Square Miles (mi2) | Square Kilometers (km2) |
|---|---|
| 0.1 mi2 | 0.259 km2 |
| 0.25 mi2 | 0.6475 km2 |
| 0.5 mi2 | 1.295 km2 |
| 1 mi2 | 2.59 km2 |
| 1.5 mi2 | 3.885 km2 |
| 2 mi2 | 5.18 km2 |
| 2.5 mi2 | 6.475 km2 |
| 3 mi2 | 7.77 km2 |
| 5 mi2 | 12.95 km2 |
| 7.5 mi2 | 19.425 km2 |
| 10 mi2 | 25.9 km2 |
| 15 mi2 | 38.85 km2 |
| 20 mi2 | 51.8 km2 |
| 25 mi2 | 64.75 km2 |
| 50 mi2 | 129.5 km2 |
| 100 mi2 | 259 km2 |
| 250 mi2 | 647.5 km2 |
| 500 mi2 | 1295 km2 |
Square Kilometers to Square Miles Conversion Table
| Square Kilometers (km2) | Square Miles (mi2) |
|---|---|
| 1 km2 | 0.3861003861 mi2 |
| 2 km2 | 0.7722007722 mi2 |
| 5 km2 | 1.9305019305 mi2 |
| 10 km2 | 3.861003861 mi2 |
| 20 km2 | 7.722007722 mi2 |
| 25 km2 | 9.6525096525 mi2 |
| 50 km2 | 19.305019305 mi2 |
| 100 km2 | 38.61003861 mi2 |
| 200 km2 | 77.2200772201 mi2 |
| 250 km2 | 96.5250965251 mi2 |
| 500 km2 | 193.0501930502 mi2 |
| 1000 km2 | 386.1003861004 mi2 |
Square Miles to Square Kilometers in Everyday Objects
Common real-world examples that make Square Miles and Square Kilometers easy to picture at a glance.
| Square Miles (mi2) | Square Kilometers (km2) | |
|---|---|---|
| Manhattan land area | 22.8 mi2 | 59.052 km2 |
| Washington, DC land area | 61.4 mi2 | 159.026 km2 |
| Central Park | 1.31 mi2 | 3.3929 km2 |
| Gibraltar | 2.6 mi2 | 6.734 km2 |
| New York City land area | 302.6 mi2 | 783.734 km2 |
| The Isle of Man | 220.8494208494 mi2 | 572 km2 |
| Rhode Island land area | 1033.8 mi2 | 2677.542 km2 |
When You Need Square Miles to Square Kilometers Conversions
Comparing City Footprints
Chicago's 227.7 sq mi converts to 589.74 sq km — the number you need when an overseas client asks how the Windy City stacks up against Madrid's 604 sq km city limits.
Wildfire Incident Reporting
When CAL FIRE or the Forest Service sizes a burn at 5 sq mi, international outlets carry it as 12.95 sq km — this converter gets your numbers wire-ready in a click.
National Park Statistics
Yellowstone's 3,471 sq mi becomes about 8,990 sq km — ideal for travel copy ranking America's first national park against metric-sized reserves abroad.
County and Municipality Sizing
A 320 sq mi Western county works out to 828.8 sq km for grant applications and international partnerships that want service-area figures in metric units.
Related Area Conversions
How to Use
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1
Enter the Area in sq mi
Type the square-mile figure from your US source — say, 22.8 sq mi for Manhattan's land area or roughly 640 sq mi for Houston
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2
See the Square Kilometers
The answer appears instantly: 22.8 sq mi = 59.05 sq km — the number international readers, journals, and wikis expect
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3
Copy or Reverse
Drop the figure straight into your report or email, or hit Swap to turn a metric figure back into square miles
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4
Check the Table
Grab quick anchors while you write: 5 sq mi = 12.95 sq km and 100 sq mi = 259 sq km
Why Use Be Converter?
Instant Conversion
See square kilometers the moment you type your square-mile figure — perfect for beating a deadline on a homework assignment or news copy
Precision Guaranteed
Uses the exact 2.59 factor from the mile's official 1.60934 km definition — no sloppy 2.6 rounding that throws off big county and state figures
Handy Reference Table
Sizes at a glance — 1 sq mi = 2.59 sq km, 50 sq mi = 129.5 sq km, 500 sq mi = 1,295 sq km — from small-town scale up to national-park scale
Swap with One Click
Flip the tool to sq km → sq mi in a single click when a metric figure from abroad needs to read naturally in an American report
Free & Unlimited
No account, no paywall. Convert every county, ranch, lake, and national park figure you need — unlimited conversions, always free
Completely Private
Everything runs locally in your browser. Nothing you type ever leaves your device — no tracking, no data collection
Frequently Asked Questions
How many square kilometers are in 1 square mile?
How do I convert 5 square miles to sq km?
What is 100 sq mi in square kilometers?
Is a square mile bigger than a square kilometer?
Why do US geography statistics use square miles?
How many sq km is Manhattan?
How many sq km is 50 square miles?
How do I convert sq mi to sq km precisely?
About Square Miles to Square Kilometers Converter
Our free sq mi to sq km converter puts American land data into the metric terms the rest of the world uses. County lines, city limits, national parks, lake surfaces, and wildfire perimeters are all logged in square miles by US agencies — and in square kilometers by everyone else. Whether you're a student, journalist, real-estate pro, or analyst, this tool applies the exact factor of 2.59 sq km per sq mi to every figure you type. No signup, no fuss, instant results right in your browser.
Expert Tips for sq mi to sq km Conversion
The 2.59 factor is a squared length ratio: 1.60934 km per mile, squared, gives 2.59 — so distances convert by 1.60934, but areas convert by 2.59.
Memorize a few city anchors: Manhattan 22.8 sq mi = 59.05 sq km, Chicago 227.7 sq mi = 589.74 sq km, and Los Angeles 468.7 sq mi = 1,213.9 sq km.
For national parks, convert before you compare: Yellowstone's 3,471 sq mi is about 8,990 sq km — roughly the size of Puerto Rico, and bigger than most European countries' parks combined.
Quick mental math: multiply sq mi by 2.6. A 320 sq mi county works out to 832 sq km against the exact 828.8 — close enough for a ballpark figure in conversation.
Watch land vs. total area: US sources often quote land only (NYC's 302.6 sq mi is land, water excluded), while metric sources sometimes include both. Match the basis on each side before converting.