Square Miles to Square Kilometers Converter

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Convert square miles to square kilometers using the exact factor 1 mi² = 2.589988 km². Reference: Manhattan ≈ 22.83 mi² ≈ 59.13 km²; the state of Texas ≈ 268,597 mi² ≈ 695,662 km². Useful for translating US/UK city, county and state sizes into the metric km² scale used on most world maps. Browser-local conversion.

Square mile (mi²)
Square kilometer (km²)

Square mile (mi²) → Square kilometer (km²)

Quick reference table

Square mile (mi²)Square kilometer (km²)
1 mi²2.59 km²
2 mi²5.18 km²
5 mi²12.9499 km²
10 mi²25.8999 km²
25 mi²64.7497 km²
50 mi²129.4994 km²
100 mi²258.9988 km²

Glossary

Square mile (mi²)

A square mile equals 640 acres or about 2.59 km² (since 1 mi = 1.609 km, 1 mi² = 1.609² km² = 2.59 km²). Used for US/UK city and county areas. The city of Chicago covers about 234 mi²; the state of Texas is about 268,597 mi². 1 km² ≈ 0.3861 mi².

Square kilometer (km²)

A square kilometer equals 1,000,000 m² or 100 hectares. It is the standard unit for city, region and country areas on metric maps. 1 km² ≈ 0.3861 mi² ≈ 247.1 acres. Note: 1 km² = 1,000,000 m² (not 1,000), because area scales as the square of length. The city of Paris covers about 105 km².

Metric / SI area

In the metric system, area is reported in square meters (SI base) and its scaled units — square millimeter, square centimeter, square kilometer — plus the convenient hectare (10,000 m²) for land. Each step is exactly 100× the previous because area scales as the square of length: 1 m² = 100 dm² = 10,000 cm² = 1,000,000 mm². This squared scaling is the most common manual-conversion error.

Imperial / US Customary area

US customary and UK imperial systems use square inch, square foot, square yard, acre and square mile (144 in² = 1 ft², 9 ft² = 1 yd², 4,840 yd² = 1 acre, 640 acres = 1 mi²). The acre — historically the area a team of oxen could plow in a day — survives as the standard land-parcel unit in the US. Linked to metric by 1 ft² = 0.09290304 m² exactly.

Related tools

Square Kilometers to Square Miles
Convert km² to mi² — 1 km² ≈ 0.3861 mi²
Acres to Square Miles
Convert acres to mi² — 640 acres = 1 mi²
Acres to Hectares
Convert acres to hectares — 1 acre ≈ 0.4047 ha
Area Converter
Convert area — mm², cm², m², ha, km², in², ft², yd², acres, mi²