Convert Astronomical Unit to Kiloparsec
Convert astronomical units to kiloparsecs instantly. 1 astronomical unit = 4.848137e-9 kiloparsec — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kiloparsec to Astronomical Unit converter for the reverse conversion.
Units explained
Astronomical Unit
The astronomical unit (AU) is a unit of length equal to exactly 149,597,870,700 meters, approximately the average distance from Earth to the Sun. It is the fundamental unit for distance within the solar system.
The AU was originally defined as the semi-major axis of Earth's orbit. In 2012, IAU Resolution B2 redefined the AU as exactly 149,597,870,700 meters, severing its dependence on the actual fluctuating Earth–Sun distance.
AUs are used to express distances within the solar system (Mars: 1.5 AU, Pluto: ~40 AU at perihelion), exoplanet orbital radii, and other planetary-scale distances. Standard in planetary science and astronomy.
Original definition tied to Earth's orbit (Newton, 17th century); fixed at exactly 149,597,870,700 m by IAU Resolution B2 in 2012.
Kiloparsec
A kiloparsec is a distance unit equal to 1,000 parsecs (about 3.09×10¹⁹ m). It is used to express galactic-scale distances.
Combines the metric-style prefix kilo- with the parsec. Standardised in astronomy as the natural unit for distances within and between galaxies.
Kiloparsecs are used to express galactic radii (the Milky Way is roughly 8 kpc from center to Sun), galactic-cluster scales, and distances within the Local Group.
Exact via the parsec; standardised by IAU 2015 along with parsec.
Astronomical Unit to Kiloparsec conversion formula
The relationship between astronomical units and kiloparsecs:
To convert astronomical units to kiloparsecs, multiply the value in astronomical units by 4.848137e-9. To reverse, multiply kiloparsecs by 2.062648e+8.
How to use this converter
Type a value into the calculator. The result in kiloparsecs updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kiloparsec to Astronomical Unit converter for the reverse direction.
Step-by-step: convert astronomical units to kiloparsecs
- Write down the value in astronomical units (AU).
- Multiply that value by the factor 4.848137e-9.
- The product is the equivalent value in kiloparsecs (kpc).
- To reverse, multiply the kiloparsec value by 2.062648e+8.
Worked examples
Example 1 — Convert 1 AU to kpc:
1 × 4.848137e-9 = 4.848137e-9 kpc
Example 2 — Convert 100 AU to kpc:
100 × 4.848137e-9 = 4.848137e-7 kpc
Astronomical Unit to Kiloparsec conversion table
Standard reference values for converting astronomical units to kiloparsecs:
| Astronomical Unit [AU] | Kiloparsec [kpc] |
|---|---|
| 0.01 | 4.848137e-11 |
| 0.1 | 4.848137e-10 |
| 1 | 4.848137e-9 |
| 2 | 9.696274e-9 |
| 3 | 1.454441e-8 |
| 4 | 1.939255e-8 |
| 5 | 2.424068e-8 |
| 10 | 4.848137e-8 |
| 20 | 9.696274e-8 |
| 30 | 1.454441e-7 |
| 40 | 1.939255e-7 |
| 50 | 2.424068e-7 |
| 100 | 4.848137e-7 |
| 500 | 2.424068e-6 |
| 1000 | 4.848137e-6 |
Frequently asked questions
How many kiloparsecs is 1 astronomical unit?
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Sources & references
Conversion factor (1 AU = 4.848137e-9 kpc) 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.