🗺️ Area converter

Square Mile to Acre Converter

Convert square miles (mi²) to acres (ac) instantly with the exact formula, a conversion table and chart.

mi²

Results

Acres
640 ac
Same value in every unit

📊 Square Mile to Acre chart

Square Mile to Acre — plotted against square mile (mi²).

How to convert square miles to acres

To convert square miles to acres, multiply by 640. Area conversions are essential for real estate, flooring, land surveys, farming and map reading.

ac = mi² × 640 mi² = ac ÷ 640
Square Mile to Acre conversion – mi² to ac formula illustration
Square Mile (mi²) → Acre (ac) at a glance.

Square Mile to Acre conversion table

Square Mile (mi²)Acre (ac)
0.1 mi²64 ac
0.5 mi²320 ac
1 mi²640 ac
2 mi²1,280 ac
3 mi²1,920 ac
4 mi²2,560 ac
5 mi²3,200 ac
10 mi²6,400 ac
20 mi²12,800 ac
25 mi²16,000 ac
50 mi²32,000 ac
100 mi²64,000 ac
500 mi²320,000 ac
1,000 mi²640,000 ac

About the units

Square Mile (mi²)

A square mile equals 640 acres, or about 2.59 square kilometers.

Acre (ac)

An acre equals 43,560 square feet (4,046.8564224 m²) and is used for land in the US and UK.

How to use this converter

  1. Type the number of square miles (mi²) in the input box.
  2. The result in acres appears instantly — no button needed.
  3. See the same value in every other area unit just below.
  4. Use “Swap units” to convert acres back to square miles.

Tips for better results

  • Double-check which system a unit belongs to (for example US vs UK gallons).
  • Use the swap button to convert in the opposite direction instantly.
  • Bookmark the conversions you use most — each pair has its own page.

Frequently asked questions

How many acres are in one square mile?

One square mile equals 640 acres. 640 is the exact factor used by this converter.

How do I convert square miles to acres?

Multiply the value in square miles by 640. To go the other way, multiply acres by 0.0015625.

What is 10 mi² in ac?

10 mi² = 6,400 ac. Also, 5 mi² = 3,200 ac and 100 mi² = 64,000 ac.

What is the difference between a square mile and a acre?

A square mile equals 640 acres, or about 2.59 square kilometers. An acre equals 43,560 square feet (4,046.8564224 m²) and is used for land in the US and UK.

Is this tool free and private?

Yes — the Square Mile to Acre is completely free with no sign-up, and it runs entirely in your browser, so the values you enter are never uploaded to our servers.

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