Square Miles to Acres (mi² to ac)
Free online square mile to acre converter. Type a value, get an instant exact result — plus the formula, a ready-made conversion table, and reverse conversion.
AREA CONVERTER — INSTANT RESULT
Formula: multiply the square mile value by 640 — i.e. ac = mi² × 640
Quick check: 1 mi² = 640 ac
Quick check: 1 mi² = 640 ac
Square Miles to Acres conversion table
| Square Miles (mi²) | Acres (ac) |
|---|---|
| 1 mi² | 640 ac |
| 2 mi² | 1,280 ac |
| 3 mi² | 1,920 ac |
| 4 mi² | 2,560 ac |
| 5 mi² | 3,200 ac |
| 6 mi² | 3,840 ac |
| 7 mi² | 4,480 ac |
| 8 mi² | 5,120 ac |
| 9 mi² | 5,760 ac |
| 10 mi² | 6,400 ac |
| 15 mi² | 9,600 ac |
| 20 mi² | 12,800 ac |
| 25 mi² | 16,000 ac |
| 30 mi² | 19,200 ac |
| 40 mi² | 25,600 ac |
| 50 mi² | 32,000 ac |
| 75 mi² | 48,000 ac |
| 100 mi² | 64,000 ac |
| 250 mi² | 160,000 ac |
| 500 mi² | 320,000 ac |
| 1,000 mi² | 640,000 ac |
How to convert square miles to acres
To convert square miles to acres, multiply the amount in square miles by 640. For example, 10 mi² = 6,400 ac. To convert in the other direction, divide by the same factor, or use the ⇄ swap button above.
Convert between metric and imperial/US land area units, including the acre (43,560 ft² exactly) and hectare (10,000 m²) used worldwide for land measurement.
Frequently asked questions
How many acres are in one square mile?
One square mile is exactly 640 acres.
How do I convert mi² to ac?
Multiply the mi² value by 640 to get ac. The converter at the top of this page does this automatically and works in both directions.
How much is 100 square miles in acres?
100 square miles equals 64,000 acres.