Convert Square US Survey Foot to Acre
Convert square us survey feet to acres instantly. 1 square us survey foot = 2.295693e-5 acre — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Acre to Square US Survey Foot converter for the reverse conversion.
Units explained
Square US Survey Foot
A square US survey foot is a unit of area equal to approximately 0.0929034116 m². It is slightly larger than the square international foot due to historical surveying definitions.
Derived by squaring the US survey foot, which was defined as exactly 1200/3937 meter from 1893 to 2023. This produced a value about 2 parts per million larger than the international foot.
Square US survey feet appear in legacy US public land records and state plane coordinate systems established before 2023. The US officially retired the survey foot effective January 1, 2023.
Defined in 1893; officially retired January 2023, but legacy records remain.
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 Foot to Acre conversion formula
The relationship between square us survey feet and acres:
To convert square us survey feet to acres, multiply the value in square us survey feet by 2.295693e-5. To reverse, multiply acres by 43559.8257617097.
How to use this converter
Type a value into the calculator. The result in acres updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Acre to Square US Survey Foot converter for the reverse direction.
Step-by-step: convert square us survey feet to acres
- Write down the value in square us survey feet (sft²).
- Multiply that value by the factor 2.295693e-5.
- The product is the equivalent value in acres (ac).
- To reverse, multiply the acre value by 43559.8257617097.
Worked examples
Example 1 — Convert 1 sft² to ac:
1 × 2.295693e-5 = 2.295693e-5 ac
Example 2 — Convert 100 sft² to ac:
100 × 2.295693e-5 = 0.0022956933 ac
Real-world example — Small to geographic-scale
100,000 square us survey feet equals one acre — a useful conversion when small-scale survey diagrams must be related to road-network distances on a different map.
100000 sft² × 2.295693e-5 = 2.2956932965 ac
Real-world example — Architectural to geographic scale
A 100,000-square us survey foot measurement equals one acre. The five-order-of-magnitude scale change comes up in mapping work where architectural site plans must be related to road-network maps.
100000 sft² × 2.295693e-5 = 2.2956932965 ac
Square US Survey Foot to Acre conversion table
Standard reference values for converting square us survey feet to acres:
| Square US Survey Foot [sft²] | Acre [ac] |
|---|---|
| 0.01 | 2.295693e-7 |
| 0.1 | 2.295693e-6 |
| 1 | 2.295693e-5 |
| 2 | 4.591387e-5 |
| 3 | 6.88708e-5 |
| 4 | 9.182773e-5 |
| 5 | 0.0001147847 |
| 10 | 0.0002295693 |
| 20 | 0.0004591387 |
| 30 | 0.000688708 |
| 40 | 0.0009182773 |
| 50 | 0.0011478466 |
| 100 | 0.0022956933 |
| 500 | 0.0114784665 |
| 1000 | 0.022956933 |
Frequently asked questions
How many acres is 1 square us survey foot?
How do I convert square us survey feet to acres?
How do I convert acres back to square us survey feet?
How many acres is 100 square us survey feet?
Popular area unit conversions
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Metric / SI (5 units)
Imperial / US Customary (3 units)
Sources & references
Conversion factor (1 sft² = 2.295693e-5 ac) 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 Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.