An astronomical unit is the mean Earth-Sun distance.
Astronomical units to Parsecs Converter — AU to pc
Convert Astronomical unit (AU) to Parsec (pc) using the exact conversion factor (1 astronomical unit = 0.0000048481 parsec). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Astronomical units to Parsecs 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 parsec is about 3.26156 light-years.
Result = input x 1.49597871e+11 / 3.08567758e+16.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Astronomical units to Parsecs
Astronomical unit and Parsec both measure length. Astronomical unit is typically associated with used internationally in astronomy for solar-system-scale distances., while Parsec is typically associated with standard distance unit throughout professional astronomy worldwide.
Formula
parsecs = astronomical units × 0.0000048481368111
This factor comes from each unit's defined relationship to the category's base unit: 1 astronomical unit equals 149597870700 base units, and 1 parsec equals 3.085678e+16 base units, so dividing one by the other gives the direct astronomical unit-to-parsec factor of 0.0000048481368111.
Simple example
1 AU × 0.000004848136811 = 0.0000048481 pc
1 astronomical unit = 0.0000048481 parsecs.
Real-world example
10 AU × 0.000004848136811 = 0.0000484814 pc
10 astronomical units = 0.0000484814 parsecs.
Conversion table
| Astronomical unit (AU) | Parsec (pc) |
|---|---|
| 1 AU | 0.0000048481 pc |
| 5 AU | 0.0000242407 pc |
| 10 AU | 0.0000484814 pc |
| 21.0975 AU | 0.0001022836 pc |
| 42.195 AU | 0.0002045671 pc |
| 100 AU | 0.0004848137 pc |
Reverse conversion: Parsec to Astronomical unit
0.0000048481 pc × 206264.8062 = 0.9999924072 AU
0.0000048481 parsecs = 0.9999924072 astronomical units.
astronomical units = parsecs × 206264.806247
For a page dedicated to this direction, see Parsec to Astronomical unit.
Astronomical unit vs. Parsec
| Aspect | Astronomical unit | Parsec |
|---|---|---|
| Family | Non-SI unit accepted for use with SI (astronomical) | non-SI unit used in astronomy |
| Typical use | Measuring distances within the solar system (planetary orbits) | Measuring distances to nearby stars via parallax |
| Where it's used | Used internationally in astronomy for solar-system-scale distances. | Standard distance unit throughout professional astronomy worldwide |
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.
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.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
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 parsecs are in 1 astronomical unit?
1 astronomical unit equals 0.0000048481 parsecs, using the exact defined conversion factor rather than an estimate.
How do I convert astronomical unit to parsec?
Multiply the astronomical unit value by 0.000004848136811. The converter above does this instantly to whatever precision you set.
How do I convert parsec back to astronomical unit?
Use the reverse factor: 1 parsec equals 206,264.8062 astronomical units. You can also use the swap control in the converter above to flip the direction instantly.
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).
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.
Is the astronomical unit to parsec 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.
Where is the astronomical unit still used today?
Used internationally in astronomy for solar-system-scale distances.