Convert Kiloparsec to Light Year
Convert kiloparsecs to light years instantly. 1 kiloparsec = 3261.5637771674 light year — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Light Year to Kiloparsec converter for the reverse conversion.
Units explained
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.
Light Year
A light year is the distance light travels in one Julian year in vacuum — exactly 9,460,730,472,580,800 meters (about 9.46×10¹⁵ m). It is the most common unit for expressing inter-stellar distances in non-technical astronomy.
Defined as the speed of light (299,792,458 m/s, exact) multiplied by one Julian year (365.25 days × 86400 seconds/day). Both factors are exact, making the light year exact by definition.
Light years are used in popular astronomy, science journalism, and stellar distance descriptions. The nearest star (Proxima Centauri) is 4.24 ly away; the Milky Way is about 100,000 ly across.
Concept of distance-as-time used since the 19th century; the modern exact definition follows from the 1983 SI definition of the meter via the speed of light.
Kiloparsec to Light Year conversion formula
The relationship between kiloparsecs and light years:
To convert kiloparsecs to light years, multiply the value in kiloparsecs by 3261.5637771674. To reverse, multiply light years by 0.0003066014.
How to use this converter
Type a value into the calculator. The result in light years updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Light Year to Kiloparsec converter for the reverse direction.
Step-by-step: convert kiloparsecs to light years
- Write down the value in kiloparsecs (kpc).
- Multiply that value by the factor 3261.5637771674.
- The product is the equivalent value in light years (ly).
- To reverse, multiply the light year value by 0.0003066014.
Worked examples
Example 1 — Convert 1 kpc to ly:
1 × 3261.5637771674 = 3261.5637771674 ly
Example 2 — Convert 100 kpc to ly:
100 × 3261.5637771674 = 326156.3777167433 ly
Kiloparsec to Light Year conversion table
Standard reference values for converting kiloparsecs to light years:
| Kiloparsec [kpc] | Light Year [ly] |
|---|---|
| 0.01 | 32.6156377717 |
| 0.1 | 326.1563777167 |
| 1 | 3261.5637771674 |
| 2 | 6523.1275543349 |
| 3 | 9784.6913315023 |
| 4 | 13046.2551086697 |
| 5 | 16307.8188858372 |
| 10 | 32615.6377716743 |
| 20 | 65231.2755433487 |
| 30 | 97846.913315023 |
| 40 | 130462.5510866973 |
| 50 | 163078.1888583717 |
| 100 | 326156.3777167433 |
| 500 | 1630781.8885837167 |
| 1000 | 3261563.7771674334 |
Frequently asked questions
How many light years is 1 kiloparsec?
How do I convert kiloparsecs to light years?
How do I convert light years back to kiloparsecs?
How many light years is 100 kiloparsecs?
Popular length unit conversions
Convert Kiloparsec to other length units
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Metric / SI (4 units)
Imperial / US Customary (4 units)
Astronomical (8 units)
Sources & references
Conversion factor (1 kpc = 3261.5637771674 ly) 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.