In 1 square miles there are 640 acres. Meanwhile in 1 acres there are 0.001563 square miles. Keep reading to learn more about each unit of measure and how they are calculated. Or just use the Acres to Square miles calculator above to convert any number.
* Values rounded to 6 decimal places for readability
To convert square miles to acres, use this fixed area conversion:
Examples:
An acre is a unit of land area, not a set shape. A piece of land can be any shape (square, rectangle, circle, or more) as long as its total area equals 1 acre = 43,560 square feet.
There are 640 acres in 1 square mile. This is a fixed conversion used for land area in the US.
Multiply the number of square miles by 640.
Formula: acres = square miles × 640
0.5 square miles = 320 acres.
Calculation: 0.5 × 640 = 320
2 square miles = 1,280 acres.
Calculation: 2 × 640 = 1,280
10 square miles = 6,400 acres.
Calculation: 10 × 640 = 6,400
An acre was set as a standard land unit, and a mile was set as a standard length. Since 1 mile = 5,280 feet, a square mile is 5,280 feet × 5,280 feet. An acre equals 43,560 square feet. When you divide square miles in square feet by square feet per acre, you get 640 acres.
Yes. 1 square mile always equals 640 acres. The numbers don’t change by region, land type, or use.
Yes. Divide acres by 640.
Formula: square miles = acres ÷ 640
1 acre = 0.0015625 square miles.
Calculation: 1 ÷ 640 = 0.0015625
A square mile is much larger. It’s based on miles, a unit of length. An acre is a smaller land unit used often for farms, lots, and parcels.
Use acres for smaller land areas like lots, farms, and parcels. Use square miles for larger areas like cities, counties, and regions. Acres can feel easier to picture when you’re working with land sales or zoning.
The conversion 1 square mile = 640 acres is standard with the international mile and acre used today. In most everyday cases, this conversion is correct and accepted.
Use 640 as your anchor.
Yes. These units measure area, not shape. A long narrow parcel and a perfect square can have the same area. If you know the area in square miles, multiplying by 640 gives the acres.
Decimals work the same way. Multiply by 640 and keep the decimals as needed.
Example: 1.75 square miles = 1.75 × 640 = 1,120 acres
It’s exact. 640 acres per square mile is a defined conversion, not an estimate. The only rounding comes from how many decimals you choose to show.
The Calculate Box tool to convert square miles to acres uses the open source script Convert.js to convert units of measurement. To use this tool, simply type a square miles value in the box and have it instantly converted to acres.