Fathom to Astronomical Unit Converter
Convert Fathom (ftm) to Astronomical Unit (AU) instantly. 1 ftm = 1.222477e-11 AU.
Length Converter
31 units available
1 ftm = 1.222477e-11 AU
Formula:
AU = ftm × 1.222477e-11With your value: 1 ftm = 1.222477e-11 AU
How big is that?
Everyday references on a logarithmic scale, all expressed in fathom so you can sanity-check the result.
Other Fathom to Astronomical Unit conversions
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 |
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 |
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.
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
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
How to Convert Fathom to Astronomical Unit
To convert from Fathom (ftm) to Astronomical Unit (AU), multiply the value by 1.222477e-11.
Formula: AU = ftm × 1.222477e-11
Reverse: ftm = AU × 8.180111e+10
Step-by-Step Example
- Start with your value in Fathom. For example: 5 ftm
- Multiply by the conversion factor: 5 x 1.222477e-11
- The result is: 6.112386e-11 AU
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.
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.
Frequently Asked Questions
How many Astronomical Unit are in 1 Fathom?
There are exactly 1.222477e-11 Astronomical Unit in 1 Fathom. This means the conversion factor from Fathom to Astronomical Unit is 1.222477e-11.
What is the formula to convert Fathom to Astronomical Unit?
The formula to convert Fathom to Astronomical Unit is: AU = ftm × 1.222477e-11. For example, to convert 10 Fathom to Astronomical Unit, you would multiply 10 by 1.222477e-11.
What is a Fathom?
The fathom equals 6 feet (1.8288 m) and is the traditional unit for water depth on nautical charts.
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 are the common uses of Fathom?
The Fathom is commonly used in sounding depth, nautical charts, diving.
Related Length Conversions
Cite this page
UnitConvertLab. (2026). Fathom to Astronomical Unit converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/fathom-to-astronomical_unit