Convert Astronomical Unit to Foot
Convert astronomical units to feet instantly. 1 astronomical unit = 4.908067e+11 foot — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Foot to Astronomical Unit converter for the reverse conversion.
Units explained
Astronomical Unit
The astronomical unit (AU) is a unit of length equal to exactly 149,597,870,700 meters, approximately the average distance from Earth to the Sun. It is the fundamental unit for distance within the solar system.
The AU was originally defined as the semi-major axis of Earth's orbit. In 2012, IAU Resolution B2 redefined the AU as exactly 149,597,870,700 meters, severing its dependence on the actual fluctuating Earth–Sun distance.
AUs are used to express distances within the solar system (Mars: 1.5 AU, Pluto: ~40 AU at perihelion), exoplanet orbital radii, and other planetary-scale distances. Standard in planetary science and astronomy.
Original definition tied to Earth's orbit (Newton, 17th century); fixed at exactly 149,597,870,700 m by IAU Resolution B2 in 2012.
Foot
A foot is an Imperial and US customary unit of length equal to 12 inches or exactly 0.3048 meters. It is the most commonly used unit of length in everyday measurement in the United States.
The foot's origin is literally the length of a human foot, used as a measurement standard since antiquity. The English foot was standardized at various points in history; the modern international foot (0.3048 m exactly) was fixed by the 1959 International Yard and Pound Agreement.
Feet are used in the US for body height, building dimensions, room sizes, road sign clearances, aviation altitude (feet above sea level), and most everyday distance estimation. The UK uses feet informally for height despite officially being metric.
Used since antiquity; standardized to 0.3048 m exactly by the International Yard and Pound Agreement of 1959. Aviation worldwide uses feet for altitude despite metric adoption elsewhere.
Astronomical Unit to Foot conversion formula
The relationship between astronomical units and feet:
To convert astronomical units to feet, multiply the value in astronomical units by 4.908067e+11. To reverse, multiply feet by 2.037462e-12.
How to use this converter
Type a value into the calculator. The result in feet updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Foot to Astronomical Unit converter for the reverse direction.
Step-by-step: convert astronomical units to feet
- Write down the value in astronomical units (AU).
- Multiply that value by the factor 4.908067e+11.
- The product is the equivalent value in feet (ft).
- To reverse, multiply the foot value by 2.037462e-12.
Worked examples
Example 1 — Convert 1 AU to ft:
1 × 4.908067e+11 = 4.908067e+11 ft
Example 2 — Convert 100 AU to ft:
100 × 4.908067e+11 = 4.908067e+13 ft
Astronomical Unit to Foot conversion table
Standard reference values for converting astronomical units to feet:
| Astronomical Unit [AU] | Foot [ft] |
|---|---|
| 0.01 | 4.908067e+9 |
| 0.1 | 4.908067e+10 |
| 1 | 4.908067e+11 |
| 2 | 9.816133e+11 |
| 3 | 1.47242e+12 |
| 4 | 1.963227e+12 |
| 5 | 2.454033e+12 |
| 10 | 4.908067e+12 |
| 20 | 9.816133e+12 |
| 30 | 1.47242e+13 |
| 40 | 1.963227e+13 |
| 50 | 2.454033e+13 |
| 100 | 4.908067e+13 |
| 500 | 2.454033e+14 |
| 1000 | 4.908067e+14 |
Frequently asked questions
How many feet is 1 astronomical unit?
How do I convert astronomical units to feet?
How do I convert feet back to astronomical units?
How many feet is 100 astronomical units?
Popular length unit conversions
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Metric / SI (4 units)
Imperial / US Customary (4 units)
Astronomical (8 units)
Sources & references
Conversion factor (1 AU = 4.908067e+11 ft) 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.