Square Miles to Square Kilometers Converter

Summary

This tool converts between square miles (mi²) and square kilometers (km²) using the exact conversion factor of 1 mi² = 2.58999 km². Enter a value in either field and the other updates instantly. No rounding surprises — results are shown to six significant figures and the full formula is displayed below the inputs.

How it works

1. Type a square-mile value in the top field — the square-kilometer result appears immediately.
2. Or type a square-kilometer value in the bottom field to convert back to square miles.
3. The conversion formula and factor are shown below both fields for transparency.
4. Click the swap button to flip which unit you are entering.
5. Use the copy button next to each result to copy the value to your clipboard.

Use cases

• Compare country or state land areas reported in different unit systems.
• Convert real-estate land parcels between US customary and metric units.
• Check geographic survey results that mix mi² and km² measurements.
• Verify textbook or Wikipedia area figures against your own calculations.
• Convert wildfire, deforestation, or flood coverage between unit systems.
• Academic geography and cartography coursework.

Frequently Asked Questions