Square Miles to Acres Converter
Convert square miles to acres: multiply by 640. 1 sq mi = 640 ac. Free calculator for large land and geographic area.
How to Convert Square mile to Acre
Multiply square miles by 640.
Conversion Formula:
value * 640Conversion Examples
Example: 1 sq mi to acres
- 1 Ă 640 = 640 ac
640 acres
Standard section scale (US).
Example: 2.5 sq mi to acres
- 2.5 Ă 640 = 1,600 ac
1,600 acres
Large holding.
Conversion Chart
| Square mile | Acre |
|---|---|
| 0.25 | 160 |
| 0.5 | 320 |
| 1 | 640 |
| 2 | 1280 |
| 3 | 1920 |
| 5 | 3200 |
| 10 | 6400 |
| 20 | 12800 |
| 50 | 32000 |
| 100 | 64000 |
Conversion Formula
square miles Ă 640 = acres
Quick Conversion Tip
Multiply sq mi by 640 for acres.
Unit Definitions
Square Mile (mi²)
A square mile is an imperial unit of area equal to the area of a square with sides measuring one mile. It equals 640 acres and is commonly used for large geographic areas, cities, and counties.
1 square mile = 640 acres = 27,878,400 square feet = 3,097,600 square yards = 2.589988 square kilometers
Acre (ac)
An acre is an imperial unit of area equal to 4,840 square yards or 43,560 square feet. It is commonly used in the United States and United Kingdom for measuring land area, especially in real estate and agriculture.
1 acre = 0.0015625 square miles = 43,560 square feet = 4,840 square yards = 4,046.8564224 square meters
Common Use Cases
- GIS and map layers in acres.
- Conservation and public-land reporting.
- Oil, gas, and mineral leases.
- Regional economic summaries.
Understanding the Conversion
1 square mile = 640 acres. Multiply sq mi by 640.
Examples: 1 sq mi = 640 ac ¡ 2 sq mi = 1,280 ac ¡ 0.5 sq mi = 320 ac.
Common when maps or GIS use sq mi but deeds and ag reports use acres.
GIS and map layers in acres. The table and FAQ on this page walk through the factor if you need it.
FAQs
How many acres in one square mile?
Exactly 640 acres per square mile.
How do you convert sq mi to acres?
Multiply square miles by 640. Example: 3 sq mi Ă 640 = 1,920 acres.
Is a section of land one square mile?
In the US Public Land Survey, a standard section is 1 sq mi (640 acres), though local exceptions exist.