Convert Kilometer to Parsec
Convert kilometers to parsecs instantly. 1 kilometer = 3.240779e-14 parsec — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Parsec to Kilometer converter for the reverse conversion.
Units explained
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
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 to Parsec conversion formula
The relationship between kilometers and parsecs:
To convert kilometers to parsecs, multiply the value in kilometers by 3.240779e-14. To reverse, multiply parsecs by 3.085678e+13.
How to use this converter
Type a value into the calculator. The result in parsecs updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Parsec to Kilometer converter for the reverse direction.
Step-by-step: convert kilometers to parsecs
- Write down the value in kilometers (km).
- Multiply that value by the factor 3.240779e-14.
- The product is the equivalent value in parsecs (pc).
- To reverse, multiply the parsec value by 3.085678e+13.
Worked examples
Example 1 — Convert 1 km to pc:
1 × 3.240779e-14 = 3.240779e-14 pc
Example 2 — Convert 100 km to pc:
100 × 3.240779e-14 = 3.240779e-12 pc
Real-world example — Endurance race distances
A 50-kilometer cycling or running race converts to a recognizable distance in parsecs. Endurance athletes coming from a different measurement system use this conversion to compare training plans across regions.
50 km × 3.240779e-14 = 1.62039e-12 pc
Real-world example — Maritime exclusion zone
A 200-kilometer exclusion zone (a common maritime boundary) converts to a different value in parsecs that's useful when describing the same zone in everyday land-distance units.
200 km × 3.240779e-14 = 6.481559e-12 pc
Real-world example — Coastal cruise distances
A 10-kilometer coastal sailing route converts to a different value in parsecs — useful for cruise operators who switch between maritime, aviation, and road-distance units depending on the leg of the trip.
10 km × 3.240779e-14 = 3.240779e-13 pc
Kilometer to Parsec conversion table
Standard reference values for converting kilometers to parsecs:
| Kilometer [km] | Parsec [pc] |
|---|---|
| 0.01 | 3.240779e-16 |
| 0.1 | 3.240779e-15 |
| 1 | 3.240779e-14 |
| 2 | 6.481559e-14 |
| 3 | 9.722338e-14 |
| 4 | 1.296312e-13 |
| 5 | 1.62039e-13 |
| 10 | 3.240779e-13 |
| 20 | 6.481559e-13 |
| 30 | 9.722338e-13 |
| 40 | 1.296312e-12 |
| 50 | 1.62039e-12 |
| 100 | 3.240779e-12 |
| 500 | 1.62039e-11 |
| 1000 | 3.240779e-11 |
Frequently asked questions
How many parsecs is 1 kilometer?
How do I convert kilometers to parsecs?
How do I convert parsecs back to kilometers?
How many parsecs is 100 kilometers?
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Astronomical (9 units)
Atomic / Physics (6 units)
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Sources & references
Conversion factor (1 km = 3.240779e-14 pc) 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.