📐 Area
sq miles to acres Converter
Convert sq miles to acres instantly with a reference table.
Quick answer: To convert sq miles to acres, multiply by 640. For example, 1 sq miles = 640 acres. Use the calculator below for any value.
sq miles to acres
→
Common conversions
| sq miles | acres |
|---|
Formula:
How to convert sq miles to acres
1
Enter your value
Type the number of sq miles you want to convert into the left box. The result in acres appears instantly in the right box. You can also type into the right box to convert in the other direction.
2
Use the swap button
Click the ⇄ Swap button to reverse the conversion — acres to sq miles. Your current value carries across so you don't have to re-enter anything.
3
About sq miles and acres
sq miles and acres are both area measurements.
💡 Did you know?
1 sq mile = 640 acres. US land in the Midwest was surveyed using the Public Land Survey System — 'townships' (6 sq miles = 3,840 acres) divided into 36 'sections' (1 sq mile = 640 acres), then half-sections, quarter-sections, and 40-acre 'forties'. Many US farm sizes are multiples of 40 acres.
📊 Common conversions at a glance
| sq miles | acres |
|---|---|
| 0.01 | 6.4 |
| 0.1 | 64 |
| 0.5 | 320 |
| 1 | 640 |
| 2 | 1280 |
| 5 | 3200 |
Reviewed for 2026. sq miles ↔ acres conversion factor verified against published reference data. Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project.