Square Miles to Acres Converter
1 square mile = 640 acres
1 square mile equals 640 acres
How to convert square miles to acres
Area factors are squared length factors: 1 ft² = (0.3048 m)². The acre here uses international feet; historic US survey acres differ slightly.
ac = mi² × 1280/2One square mile is 1280/2 acres, so a single multiplication converts any value.
6,400 ac = 10 × 1280/2Square miles to acres conversion table
Common values in square miles, converted to acres.
| Square miles (mi²) | Acres (ac) |
|---|---|
| 1 | 640 |
| 2 | 1,280 |
| 3 | 1,920 |
| 4 | 2,560 |
| 5 | 3,200 |
| 10 | 6,400 |
| 20 | 12,800 |
| 25 | 16,000 |
| 50 | 32,000 |
| 100 | 64,000 |
| 250 | 160,000 |
| 500 | 320,000 |
| 1,000 | 640,000 |
About these units
square milemi²
Exactly 640 acres. Used for county and country areas.
acreac
Exactly 4,840 square yards, or 43,560 square feet. The customary land unit.
Reference: Derived from the international yard (1959).
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.