A parsec is about 3.26156 light-years.
Parsecs to Astronomical units Converter — pc to AU
Convert Parsec (pc) to Astronomical unit (AU) using the exact conversion factor (1 parsec = 206,264.8062 astronomical unit). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Parsecs to Astronomical units converter
Converter
Astronomy Converter
Convert astronomical length, mass, time, and distance units by compatible family.
Context values
Some unit families need one extra value for a physically accurate result.
An astronomical unit is the mean Earth-Sun distance.
Result = input x 3.08567758e+16 / 1.49597871e+11.
Distance units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Parsecs to Astronomical units
Parsec and Astronomical unit both describe astronomical distances at very different scales — one for measuring within our solar system, the other for the distances between stars — and converting between them helps put the scale of space into perspective. Parsec is typically associated with standard distance unit throughout professional astronomy worldwide, while Astronomical unit is typically associated with used internationally in astronomy for solar-system-scale distances..
Formula
astronomical units = parsecs × 206264.806247
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 astronomical unit equals 149597870700 base units, so dividing one by the other gives the direct parsec-to-astronomical unit factor of 206264.806247.
Simple example
1 pc × 206264.8062 = 206,264.8062 AU
1 parsec = 206,264.8062 astronomical units.
Real-world example
4.24 pc × 206264.8062 = 874,562.7785 AU
4.24 parsecs = 874,562.7785 astronomical units.
Conversion table
| Parsec (pc) | Astronomical unit (AU) |
|---|---|
| 1 pc | 206,264.8062 AU |
| 4.24 pc | 874,562.7785 AU |
| 10 pc | 2,062,648.062 AU |
| 100 pc | 20,626,480.62 AU |
| 1,000 pc | 206,264,806.2 AU |
| 1,000,000 pc | 206,264,806,200 AU |
Reverse conversion: Astronomical unit to Parsec
1 AU × 0.000004848136811 = 0.0000048481 pc
1 astronomical unit = 0.0000048481 parsecs.
parsecs = astronomical units × 0.0000048481368111
For a page dedicated to this direction, see Astronomical unit to Parsec.
Parsec vs. Astronomical unit
| Aspect | Parsec | Astronomical unit |
|---|---|---|
| Family | non-SI unit used in astronomy | Non-SI unit accepted for use with SI (astronomical) |
| Typical use | Measuring distances to nearby stars via parallax | Measuring distances within the solar system (planetary orbits) |
| Where it's used | Standard distance unit throughout professional astronomy worldwide | Used internationally in astronomy for solar-system-scale distances. |
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 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.
Parsec — sources
- IAU (International Astronomical Union) — parsec definition — Standard astronomical definition of the parsec via stellar parallax.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many astronomical units are in 1 parsec?
1 parsec equals 206,264.8062 astronomical units, using the exact defined conversion factor rather than an estimate.
How do I convert parsec to astronomical unit?
Multiply the parsec value by 206264.8062. The converter above does this instantly to whatever precision you set.
How do I convert astronomical unit back to parsec?
Use the reverse factor: 1 astronomical unit equals 0.0000048481 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 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).
Is the parsec to astronomical unit 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 parsec still used today?
Standard distance unit throughout professional astronomy worldwide