Square Miles to Square Kilometers

What is the mi² to km² Converter?

This tool converts square miles to square kilometers, the international standard for measuring large geographic areas.

Why Convert to Square Kilometers?

Square kilometers are used by most of the world, the United Nations, and all scientific publications. Converting US measurements is necessary when:

• Writing for international audiences — readers expect metric units
• Scientific research — academic journals require SI units
• International collaboration — working with global teams
• Comparing with world data — most geographic databases use km²

The Conversion

1 square mile = 2.59 square kilometers

Texas (268,596 mi²) equals 695,662 km², making it comparable in size to Myanmar or Afghanistan. Alaska (663,300 mi²) equals 1.72 million km², larger than many European countries combined.

Metric Adoption

The US is one of only three countries not officially using the metric system. For international communication, converting to square kilometers is essential for clarity and precision.

How to Use

1. Enter square miles — type the US geographic area
2. View square kilometers — the metric result appears instantly
3. Use internationally — in papers, presentations, or communications

US State Sizes in Metric

Major US states converted to square kilometers:

• Alaska (663,300 mi²) = 1,717,854 km² — larger than Mongolia
• Texas (268,596 mi²) = 695,662 km² — similar to Myanmar
• California (163,696 mi²) = 423,970 km² — close to Iraq's size
• Montana (147,040 mi²) = 380,832 km² — similar to Japan
• New York (54,556 mi²) = 141,300 km² — close to Greece

Scientific Communication

When publishing research about US wildlife habitats, protected areas, or climate zones, metric conversion ensures your data integrates seamlessly with global datasets.

Reverse Conversion

Click the swap button (↔) to convert square kilometers to square miles.

Converter Features

Instant Real-Time Conversion

See square kilometer equivalents as you type. Convert US geographic data for international audiences instantly.

Bidirectional Conversion

Switch between mi² and km² with one click. Work in whichever direction your research requires.

One-Click Copy

Copy metric results for scientific papers, international reports, or global databases.

US Geography in Metric

American geographic references in km²:

• Manhattan (23 mi²) = 59 km²
• Rhode Island (1,545 mi²) = 4,001 km²
• Texas (268,596 mi²) = 695,662 km²
• Alaska (663,300 mi²) = 1,717,854 km²

Mobile-Optimized Design

Convert US data to metric on your phone when collaborating with international colleagues or writing for global audiences.

Frequently Asked Questions

How do I convert square miles to square kilometers?

Multiply square miles by 2.59. For example, 100 mi² × 2.59 = 259 km².

Why should I convert to square kilometers?

Scientific journals, international organizations, and most of the world use km². Converting ensures your data is accessible globally and compatible with other research.

What's the quick mental math for mi² to km²?

Multiply by 2.5 for a quick estimate. For 100 mi²: 100 × 2.5 = 250 km². The exact answer is 259 km²—close enough for quick comparisons.

How does the US compare to other countries in km²?

The contiguous US (3.12M mi²) = 8.08M km². This makes it comparable to Brazil (8.51M km²) or slightly smaller than China (9.6M km²).

Do scientific papers accept square miles?

Generally no. International scientific publications require SI units. Convert to km² for submission, even when studying US geography.

How accurate is this converter?

The converter uses the precise factor: 1 mi² = 2.58998811 km². Results are mathematically exact for scientific accuracy.