Astronomical Unit to Fathom Converter
Convert Astronomical Unit (AU) to Fathom (ftm) instantly. 1 AU = 81,801,110,400.26247 ftm.
Length Converter
31 units available
1 AU = 81,801,110,400.26247 ftm
Formula:
ftm = AU × 8.180111e+10With your value: 1 AU = 81,801,110,400.26247 ftm
How big is that?
Everyday references on a logarithmic scale, all expressed in astronomical unit so you can sanity-check the result.
Other Astronomical Unit to Fathom conversions
Astronomical Unit to Fathom Conversion Table
| Astronomical Unit (AU) | Fathom (ftm) |
|---|---|
| 0.5 | 40,900,555,200.13123 |
| 1 | 81,801,110,400.26247 |
| 2 | 163,602,220,800.52493 |
| 5 | 409,005,552,001.3123 |
| 10 | 818,011,104,002.6246 |
| 15 | 1.227017e+12 |
| 20 | 1.636022e+12 |
| 25 | 2.045028e+12 |
| 50 | 4.090056e+12 |
| 100 | 8.180111e+12 |
| 250 | 2.045028e+13 |
| 500 | 4.090056e+13 |
| 1000 | 8.180111e+13 |
Fathom to Astronomical Unit Conversion Table
| Fathom (ftm) | Astronomical Unit (AU) |
|---|---|
| 0.5 | 6.112386e-12 |
| 1 | 1.222477e-11 |
| 2 | 2.444955e-11 |
| 5 | 6.112386e-11 |
| 10 | 1.222477e-10 |
| 15 | 1.833716e-10 |
| 20 | 2.444955e-10 |
| 25 | 3.056193e-10 |
| 50 | 6.112386e-10 |
| 100 | 1.222477e-9 |
| 250 | 3.056193e-9 |
| 500 | 6.112386e-9 |
| 1000 | 1.222477e-8 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Astronomical Unit (AU)
Length
The astronomical unit is exactly 149 597 870 700 m (IAU Resolution B2, 2012).
Source: IAU Resolution B2 (2012) — definition of the astronomical unit; IAU B2 (2015) nominal values
International Astronomical Union · Reviewed 2026-07-01
Fathom (ftm)
Length
Traceable to the metre, defined by fixing the speed of light in vacuum at 299 792 458 m/s. Imperial lengths derive from the 1959 international yard (0.9144 m exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
How to Convert Astronomical Unit to Fathom
To convert from Astronomical Unit (AU) to Fathom (ftm), multiply the value by 81,801,110,400.26247.
Formula: ftm = AU × 8.180111e+10
Reverse: AU = ftm × 1.222477e-11
Step-by-Step Example
- Start with your value in Astronomical Unit. For example: 5 AU
- Multiply by the conversion factor: 5 x 81,801,110,400.26247
- The result is: 409,005,552,001.3123 ftm
About Astronomical Unit
The astronomical unit (AU) is defined as exactly 149,597,870,700 metres, close to the mean Earth–Sun distance. It is the natural yardstick for the Solar System.
Common uses: planetary science, orbital mechanics, astronomy.
About Fathom
The fathom equals 6 feet (1.8288 m) and is the traditional unit for water depth on nautical charts.
Fun Fact: The word comes from the Old English "fæðm", the span of a man's outstretched arms.
Common uses: sounding depth, nautical charts, diving.
Frequently Asked Questions
How many Fathom are in 1 Astronomical Unit?
There are exactly 81,801,110,400.26247 Fathom in 1 Astronomical Unit. This means the conversion factor from Astronomical Unit to Fathom is 81,801,110,400.26247.
What is the formula to convert Astronomical Unit to Fathom?
The formula to convert Astronomical Unit to Fathom is: ftm = AU × 8.180111e+10. For example, to convert 10 Astronomical Unit to Fathom, you would multiply 10 by 81,801,110,400.26247.
What is a Astronomical Unit?
The astronomical unit (AU) is defined as exactly 149,597,870,700 metres, close to the mean Earth–Sun distance. It is the natural yardstick for the Solar System.
What is a Fathom?
The fathom equals 6 feet (1.8288 m) and is the traditional unit for water depth on nautical charts.
What are the common uses of Astronomical Unit?
The Astronomical Unit is commonly used in planetary science, orbital mechanics, astronomy.
Related Length Conversions
Cite this page
UnitConvertLab. (2026). Astronomical Unit to Fathom converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/astronomical_unit-to-fathom