Convert Parsec to Kilometer
Convert parsecs to kilometers instantly. 1 parsec = 3.085678e+13 kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilometer to Parsec converter for the reverse conversion.
Units explained
Parsec
A parsec (parallax-second) is a distance unit equal to 648,000/π astronomical units — approximately 3.086×10¹⁶ m (3.26 light years). It is the standard distance unit in professional astronomy.
Defined as the distance at which one astronomical unit subtends an angle of one arcsecond. IAU Resolution B2 in 2015 made this an exact definition: 1 pc = (648,000/π) AU.
Parsecs are used in professional astronomy for stellar distances (Proxima Centauri ≈ 1.3 pc), galactic-scale distances (with prefixes kiloparsec and megaparsec), and parallax measurements. Standard since the early 20th century.
Concept introduced by Herbert Hall Turner in 1913; exact definition via the AU adopted by IAU Resolution B2 in 2015.
Kilometer
A kilometer is a metric unit of length equal to one thousand meters. It is the standard unit for measuring road distances, geographic distances, and other large-scale measurements in metric countries.
The kilometer was defined alongside the meter in 1795 using the standard SI prefix kilo- (from Greek chilioi, "thousand"), denoting one thousand units.
Kilometers are used worldwide (except the United States and a few others) for road signage, geographic distance, athletic events, and scientific distances at planetary scale. Speed limits in most countries are given in km/h.
Adopted 1795 in France as part of the original metric system; the kilometer became the global standard for road and geographic distance through the 19th and 20th century metric adoption.
Parsec to Kilometer conversion formula
The relationship between parsecs and kilometers:
To convert parsecs to kilometers, multiply the value in parsecs by 3.085678e+13. To reverse, multiply kilometers by 3.240779e-14.
How to use this converter
Type a value into the calculator. The result in kilometers updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilometer to Parsec converter for the reverse direction.
Step-by-step: convert parsecs to kilometers
- Write down the value in parsecs (pc).
- Multiply that value by the factor 3.085678e+13.
- The product is the equivalent value in kilometers (km).
- To reverse, multiply the kilometer value by 3.240779e-14.
Worked examples
Example 1 — Convert 1 pc to km:
1 × 3.085678e+13 = 3.085678e+13 km
Example 2 — Convert 100 pc to km:
100 × 3.085678e+13 = 3.085678e+15 km
Parsec to Kilometer conversion table
Standard reference values for converting parsecs to kilometers:
| Parsec [pc] | Kilometer [km] |
|---|---|
| 0.01 | 3.085678e+11 |
| 0.1 | 3.085678e+12 |
| 1 | 3.085678e+13 |
| 2 | 6.171355e+13 |
| 3 | 9.257033e+13 |
| 4 | 1.234271e+14 |
| 5 | 1.542839e+14 |
| 10 | 3.085678e+14 |
| 20 | 6.171355e+14 |
| 30 | 9.257033e+14 |
| 40 | 1.234271e+15 |
| 50 | 1.542839e+15 |
| 100 | 3.085678e+15 |
| 500 | 1.542839e+16 |
| 1000 | 3.085678e+16 |
Frequently asked questions
How many kilometers is 1 parsec?
How do I convert parsecs to kilometers?
How do I convert kilometers back to parsecs?
How many kilometers is 100 parsecs?
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Sources & references
Conversion factor (1 pc = 3.085678e+13 km) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.