Acres to Square Miles Converter

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Convert acres to square miles using the exact imperial relation 1 mi² = 640 acres. Anchors: 320 acres = 0.5 mi², 640 acres = 1 mi², 6,400 acres = 10 mi². Practical for large rural/ranch parcels and US Land Survey grid references where 640-acre sections form one square mile. Browser-local.

Acre
Square mile (mi²)

Acre → Square mile (mi²)

Quick reference table

AcreSquare mile (mi²)
1 acre0.0016 mi²
2 acre0.0031 mi²
5 acre0.0078 mi²
10 acre0.0156 mi²
25 acre0.0391 mi²
50 acre0.0781 mi²
100 acre0.1563 mi²

Glossary

Acre

An acre is exactly 43,560 ft² or about 4,046.86 m² (≈ 0.4047 hectares). The unit dates from medieval England, originally defined as the land a yoke of oxen could plow in a day. Standard for US farmland, real-estate lots and conservation land. 640 acres make one square mile; a typical American suburban house lot is 0.2–0.5 acres.

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.

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