Convert Square Chain to Square Mile
Convert square chains to square miles instantly. 1 square chain = 0.00015625 square mile — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Mile to Square Chain converter for the reverse conversion.
Units explained
Square Chain
A square chain is an imperial unit of area equal to approximately 404.686 m². It equals 1/10 of an acre.
Derived by squaring the chain (66 feet or 22 yards). The chain was defined by Edmund Gunter in 1620 specifically so that 10 square chains equal exactly one acre.
Square chains appear in US Public Land Survey System (PLSS) records and historical English property documents. The 10-to-1 ratio with acres made early survey arithmetic easier.
Defined by Edmund Gunter in 1620 specifically for surveying convenience.
Square Mile
A square mile is an imperial unit of area equal to exactly 2,589,988.110336 m². It is used for measuring large land areas in the United States and the United Kingdom.
Derived by squaring the statute mile (5,280 feet). The mile was standardized via the 1959 International Yard and Pound Agreement.
Square miles are used for US and UK regional geography (county areas, lake sizes, large parks), national statistics, and military range descriptions. 1 mi² = 640 acres = 2.589988 km².
Mile dates to Roman antiquity; modern exact value standardized in 1959.
Square Chain to Square Mile conversion formula
The relationship between square chains and square miles:
To convert square chains to square miles, multiply the value in square chains by 0.00015625. To reverse, multiply square miles by 6400.0000006326.
How to use this converter
Type a value into the calculator. The result in square miles updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Square Mile to Square Chain converter for the reverse direction.
Step-by-step: convert square chains to square miles
- Write down the value in square chains (ch²).
- Multiply that value by the factor 0.00015625.
- The product is the equivalent value in square miles (mi²).
- To reverse, multiply the square mile value by 6400.0000006326.
Worked examples
Example 1 — Convert 1 ch² to mi²:
1 × 0.00015625 = 0.00015625 mi²
Example 2 — Convert 100 ch² to mi²:
100 × 0.00015625 = 0.015625 mi²
Square Chain to Square Mile conversion table
Standard reference values for converting square chains to square miles:
| Square Chain [ch²] | Square Mile [mi²] |
|---|---|
| 0.01 | 1.5625e-6 |
| 0.1 | 1.5625e-5 |
| 1 | 0.00015625 |
| 2 | 0.0003125 |
| 3 | 0.00046875 |
| 4 | 0.000625 |
| 5 | 0.00078125 |
| 10 | 0.0015625 |
| 20 | 0.003125 |
| 30 | 0.0046875 |
| 40 | 0.00625 |
| 50 | 0.0078125 |
| 100 | 0.015625 |
| 500 | 0.078125 |
| 1000 | 0.15625 |
Frequently asked questions
How many square miles is 1 square chain?
How do I convert square chains to square miles?
How do I convert square miles back to square chains?
How many square miles is 100 square chains?
Popular area unit conversions
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Metric / SI (5 units)
Imperial / US Customary (14 units)
Sources & references
Conversion factor (1 ch² = 0.00015625 mi²) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.