Convert Acre to Square US Survey Mile
Convert acres to square us survey miles instantly. 1 acre = 0.0015624938 square us survey mile — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square US Survey Mile to Acre converter for the reverse conversion.
Units explained
Acre
An acre is an imperial unit of area equal to exactly 4046.8564224 m². It is the most widely used non-metric unit for land area, particularly in the US, UK, and India.
Originally defined in medieval England as the area one yoke of oxen could plow in a day, approximately 40 perches by 4 perches. Standardized via the 1959 International Yard and Pound Agreement.
Acres are the standard land measurement unit in the US (real estate, agriculture), the UK (rural property), and widely used in India (alongside hectares and traditional regional units). 1 acre = 4840 sq yd = 43,560 sq ft = 0.4047 hectare.
Medieval English farming origin; modern exact value standardized in 1959.
Square US Survey Mile
A square US survey mile is approximately 2,589,998 m², slightly larger than the international square mile.
Derived by squaring the US survey mile (5280 US survey feet).
Square US survey miles appear in older US Public Land Survey System records and state plane coordinate systems pre-dating 2023.
Defined in 1893; retired January 2023.
Acre to Square US Survey Mile conversion formula
The relationship between acres and square us survey miles:
To convert acres to square us survey miles, multiply the value in acres by 0.0015624938. To reverse, multiply square us survey miles by 640.0025599287.
How to use this converter
Type a value into the calculator. The result in square us survey 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 US Survey Mile to Acre converter for the reverse direction.
Step-by-step: convert acres to square us survey miles
- Write down the value in acres (ac).
- Multiply that value by the factor 0.0015624938.
- The product is the equivalent value in square us survey miles (smi²).
- To reverse, multiply the square us survey mile value by 640.0025599287.
Worked examples
Example 1 — Convert 1 ac to smi²:
1 × 0.0015624938 = 0.0015624938 smi²
Example 2 — Convert 100 ac to smi²:
100 × 0.0015624938 = 0.156249375 smi²
Real-world example — Endurance race distances
A 50-acre cycling or running race converts to a recognizable distance in square us survey miles. Endurance athletes coming from a different measurement system use this conversion to compare training plans across regions.
50 ac × 0.0015624938 = 0.0781246875 smi²
Real-world example — Maritime exclusion zone
A 200-acre exclusion zone (a common maritime boundary) converts to a different value in square us survey miles that's useful when describing the same zone in everyday land-distance units.
200 ac × 0.0015624938 = 0.31249875 smi²
Real-world example — Coastal cruise distances
A 10-acre coastal sailing route converts to a different value in square us survey miles — useful for cruise operators who switch between maritime, aviation, and road-distance units depending on the leg of the trip.
10 ac × 0.0015624938 = 0.0156249375 smi²
Acre to Square US Survey Mile conversion table
Standard reference values for converting acres to square us survey miles:
| Acre [ac] | Square US Survey Mile [smi²] |
|---|---|
| 0.01 | 1.562494e-5 |
| 0.1 | 0.0001562494 |
| 1 | 0.0015624938 |
| 2 | 0.0031249875 |
| 3 | 0.0046874813 |
| 4 | 0.006249975 |
| 5 | 0.0078124688 |
| 10 | 0.0156249375 |
| 20 | 0.031249875 |
| 30 | 0.0468748125 |
| 40 | 0.06249975 |
| 50 | 0.0781246875 |
| 100 | 0.156249375 |
| 500 | 0.7812468751 |
| 1000 | 1.5624937502 |
Frequently asked questions
How many square us survey miles is 1 acre?
How do I convert acres to square us survey miles?
How do I convert square us survey miles back to acres?
How many square us survey miles is 100 acres?
Popular area unit conversions
Convert Acre to other area units
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Metric / SI (16 units)
Imperial / US Customary (14 units)
US Survey (5 units)
Indian Subcontinent (16 units)
Other Regional (10 units)
Scientific / Physics (5 units)
Historical / Pre-metric European (6 units)
Sources & references
Conversion factor (1 ac = 0.0015624938 smi²) 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.