The US survey foot is 1200/3937 meters and is retained for legacy land records.
US survey feet to Astronomical units Converter — ftUS to AU
Convert US survey foot (ftUS) to Astronomical unit (AU) using the exact conversion factor (1 us survey foot = 2.037466e-12 astronomical unit). See the formula, worked examples, conversion table, history, and common uses.
US survey feet to Astronomical units converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
An astronomical unit is the mean Earth-Sun distance.
Result = input x 0.3048006096 / 1.49597871e+11.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting US survey feet to Astronomical units
US survey foot and Astronomical unit both measure length. Specifically: The US survey foot is 1200/3937 meters and is retained for legacy land records, and an astronomical unit is the mean Earth-Sun distance.
Formula
astronomical units = us survey feet × 2.037466e-12
This factor comes from each unit's defined relationship to the category's base unit: 1 us survey foot equals 0.304800609601 base units, and 1 astronomical unit equals 149597870700 base units, so dividing one by the other gives the direct us survey foot-to-astronomical unit factor of 2.037466e-12.
Simple example
1 ftUS × 2.037466e-12 = 2.037466e-12 AU
1 us survey foot = 2.037466e-12 astronomical units.
Real-world example
10 ftUS × 2.037466e-12 = 2.037466e-11 AU
10 us survey feet = 2.037466e-11 astronomical units.
Conversion table
| US survey foot (ftUS) | Astronomical unit (AU) |
|---|---|
| 1 ftUS | 2.037466e-12 AU |
| 5 ftUS | 1.018733e-11 AU |
| 10 ftUS | 2.037466e-11 AU |
| 21.0975 ftUS | 4.298544e-11 AU |
| 42.195 ftUS | 8.597089e-11 AU |
| 100 ftUS | 2.037466e-10 AU |
Reverse conversion: Astronomical unit to US survey foot
2.037466e-12 AU × 490805680800 = 0.9999998872 ftUS
2.037466e-12 astronomical units = 0.9999998872 us survey feet.
us survey feet = astronomical units × 490805680788
For a page dedicated to this direction, see Astronomical unit to US survey foot.
Understanding the US survey foot (ftUS)
The US survey foot is 1200/3937 meters and is retained for legacy land records.
Understanding the Astronomical unit
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Where it's used: Used internationally in astronomy for solar-system-scale distances.
Uses of the Astronomical unit today
- Measuring distances within the solar system (planetary orbits)
- Astronomical calculations and spacecraft navigation
- Popular science communication about the solar system
History of the Astronomical unit
The astronomical unit originated from 17th-19th century attempts to measure the Earth-Sun distance, refined over time using transits of Venus and later radar and spacecraft ranging.
In 2012, the International Astronomical Union fixed the AU at exactly 149,597,870,700 meters, replacing its earlier definition (tied to gravitational calculations) with a simple fixed distance, independent of the slightly-variable actual Earth-Sun distance.
Historical origin. Astronomical unit was not the invention of a single named person; it developed through the process described above.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many astronomical units are in 1 us survey foot?
1 us survey foot equals 2.037466e-12 astronomical units, using the exact defined conversion factor rather than an estimate.
How do I convert us survey foot to astronomical unit?
Multiply the us survey foot value by 2.037466e-12. The converter above does this instantly to whatever precision you set.
How do I convert astronomical unit back to us survey foot?
Use the reverse factor: 1 astronomical unit equals 490,805,680,800 us survey feet. You can also use the swap control in the converter above to flip the direction instantly.
What is a us survey foot?
US survey foot (ftUS) is a unit of length.
What is a astronomical unit?
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Is the us survey foot to astronomical unit conversion exact?
Yes. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.