A parsec is about 3.26156 light-years.
Parsecs to Fathoms Converter — pc to ftm
Convert Parsec (pc) to Fathom (ftm) using the exact conversion factor (1 parsec = 1.687269e+16 fathom). See the formula, worked examples, conversion table, history, and common uses.
Parsecs to Fathoms 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.
A fathom is six feet.
Result = input x 3.08567758e+16 / 1.8288.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Parsecs to Fathoms
Parsec and Fathom both measure length. Parsec is most often used for measuring distances to nearby stars via parallax.
Formula
fathoms = parsecs × 1.687269e+16
This factor comes from each unit's defined relationship to the category's base unit: 1 parsec equals 3.085678e+16 base units, and 1 fathom equals 1.8288 base units, so dividing one by the other gives the direct parsec-to-fathom factor of 1.687269e+16.
Simple example
1 pc × 1.687269e+16 = 1.687269e+16 ftm
1 parsec = 1.687269e+16 fathoms.
Real-world example
10 pc × 1.687269e+16 = 1.687269e+17 ftm
10 parsecs = 1.687269e+17 fathoms.
Conversion table
| Parsec (pc) | Fathom (ftm) |
|---|---|
| 1 pc | 1.687269e+16 ftm |
| 5 pc | 8.436345e+16 ftm |
| 10 pc | 1.687269e+17 ftm |
| 21.0975 pc | 3.559716e+17 ftm |
| 42.195 pc | 7.119432e+17 ftm |
| 100 pc | 1.687269e+18 ftm |
Reverse conversion: Fathom to Parsec
1.687269e+16 ftm × 5.926737e-17 = 0.9999999889 pc
1.687269e+16 fathoms = 0.9999999889 parsecs.
parsecs = fathoms × 5.926737e-17
For a page dedicated to this direction, see Fathom to Parsec.
Understanding the Parsec
Parsec (pc) measures astronomical distance. The distance at which one astronomical unit subtends an angle of one arcsecond — approximately 3.26 light-years, or about 3.086 × 10¹⁶ meters. It is classified as a non-SI unit used in astronomy.
Where it's used: Standard distance unit throughout professional astronomy worldwide
Uses of the Parsec today
- Measuring distances to nearby stars via parallax
- Galactic and extragalactic distance scales in astrophysics research
History of the Parsec
The name is a portmanteau of 'parallax' and 'arcsecond,' reflecting how the unit is defined directly from the parallax method astronomers use to measure stellar distances: the tiny apparent shift in a nearby star's position as Earth orbits the Sun.
Historical origin. Parsec was not the invention of a single named person; it developed through the process described above.
Understanding the Fathom (ftm)
A fathom is six feet.
Parsec — sources
- IAU (International Astronomical Union) — parsec definition — Standard astronomical definition of the parsec via stellar parallax.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many fathoms are in 1 parsec?
1 parsec equals 1.687269e+16 fathoms, using the exact defined conversion factor rather than an estimate.
How do I convert parsec to fathom?
Multiply the parsec value by 1.687269e+16. The converter above does this instantly to whatever precision you set.
How do I convert fathom back to parsec?
Use the reverse factor: 1 fathom equals 5.926737e-17 parsecs. You can also use the swap control in the converter above to flip the direction instantly.
What is a parsec?
Parsec (pc) measures astronomical distance. The distance at which one astronomical unit subtends an angle of one arcsecond — approximately 3.26 light-years, or about 3.086 × 10¹⁶ meters. It is classified as a non-SI unit used in astronomy.
What is a fathom?
Fathom (ftm) is a unit of length.
Is the parsec to fathom conversion exact?
Yes. Both parsec and fathom are defined by fixed standards rather than physical artifacts, so the factor of 1.687269e+16 used above is exact to as many digits as you choose to display.
Where is the parsec still used today?
Standard distance unit throughout professional astronomy worldwide