Convert Square Mile to Acre
Use this free converter to change square miles (mi²) into acres (ac). Square mile and acre both measure area. As a quick reference, 1 mi² equals 640 ac, and 1 ac equals 0.0015625 mi².
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Acre (ac)
640
1 mi² = 640 ac
Area conversion table
| Square Mile | Acre |
|---|---|
| 0.01 | 6.4 |
| 0.1 | 64 |
| 0.5 | 320 |
| 1 | 640 |
| 2 | 1280 |
| 3 | 1920 |
| 5 | 3200 |
| 10 | 6400 |
| 20 | 12800 |
| 25 | 16000 |
| 50 | 32000 |
| 100 | 64000 |
| 1,000 | 640000 |
How to convert Square Mile to Acre
Multiply the square mile value by 640 to get acres.
- Enter the number of square miles you want to convert.
- The converter instantly shows the equivalent value in acres.
- Worked example: 15 mi² × 640 = 9600 ac.
- Use the swap button to reverse the conversion (acre to square mile).
About these units
Square Mile (mi²)
- Definition
- A square mile (mi²) is the area of a square one mile on each side, about 2.59 square kilometers.
- History
- It derives from the statute mile of English origin.
- Current use
- Square miles express land area and population density in the US and UK.
Acre (ac)
- Definition
- An acre (ac) is a unit of land area equal to 43,560 square feet, or about 4,047 square meters.
- History
- Originally the area a yoke of oxen could plough in a day, it was standardised in medieval England.
- Current use
- Acres measure farmland and real-estate plots in the US and UK.
Frequently asked questions
How many acres are in a square mile?
There are 640 ac in 1 mi². To convert, multiply the number of square miles by 640.
How do I convert square miles to acres?
Multiply the square mile value by 640 to get acres. For example, 10 mi² = 6400 ac.
Is this square mile-to-acre converter free?
Yes. This converter is completely free, runs entirely in your browser, and requires no sign-up. Your inputs never leave your device.
Convert Square Mile to other area units
| Unit | 1 Square Mile equals |
|---|---|
| Square Meter (m²) | 2589988.1 m² |
| Square Kilometer (km²) | 2.5899881 km² |
| Square Centimeter (cm²) | 25899881000 cm² |
| Square Yard (yd²) | 3097600 yd² |
| Square Foot (ft²) | 27878400 ft² |
| Square Inch (in²) | 4014489600 in² |
| Acre (ac) | 640 ac |
| Hectare (ha) | 258.99881 ha |