Convert

Parsec to Light-year

Exact answer: 1 pc = 3.261563777167 Lj (IAU definition, exact)

Parsec and Light-year are astronomical lengths. Both are defined by exact constants, not by measurements. Length figures range from nanometres in semiconductor manufacturing to astronomical distances, and inch, foot and mile come from a different system of units.

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Convert units with formula, context and precision

UnitCloud is a local measurement lab for everyday work, engineering, IT, energy, mobility and design. Every conversion shows result, formula, base unit, rounding and the common mistake.

What do you want to convert?

From1 pc

Result3.261564 Lj

Factor1 pc = 3.261563777167 Lj

Source basisBIPM SI Brochure · NIST Guide to SI Appendix B

Examples

011 pc = 3.261564 Lj

Example value from the reference table. Internal calculation uses stored factors; display output is rounded.

02Common mistake

Inch, foot and mile use fixed factors. Errors usually come from early rounding or from mixing land miles and nautical miles.

03Base unit: m

1 pc = 3.085677581491367e16 m. Then the value is converted through the base unit m into Light-year.

Table

Parsec to Light-year
Parsec	Light-year
1	3.261564
2	6.523128
5	16.307819
10	32.615638
100	326.156378
1,000	3,261.563777

Formula

1 pc = 3.085677581491367e16 m. Then the value is converted through the base unit m into Light-year.

Sources

BIPM SI BrochureSI base units, prefixes and official SI context.NIST Guide to SI Appendix BNIST conversion-factor method and non-SI factors.

Related conversions

Light-year to KilometreLj → kmLength Kilometre to Light-yearkm → LjLength Light-year to ParsecLj → pcLength Inch to Centimetrein → cmLength

Search and practice paths

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Factor origin

Factors come from the stored source family and are not derived from rounded display values.

Rounding rule

UnitCloud keeps calculating with stored factors and rounds only the displayed output by selected precision.

When not to use

Do not use as the sole basis for official, medical, safety-critical or contractual decisions.

Citation

Citation note: UnitCloud, conversion with formula, sources reviewed: September 2026. Length. Source basis: BIPM SI Brochure · NIST Guide to SI Appendix B.

Common questions

What is the factor for Parsec to Light-year?

1 pc = 3.261563777167 Lj

Which formula does Parsec to Light-year use?

1 pc = 3.085678e16 m. Then the value is converted through the base unit m into Light-year.

What is the most common mistake?

Inch, foot and mile use fixed factors. Errors usually come from early rounding or from mixing land miles and nautical miles.

When should I verify the result?

Do not use as the sole basis for official, medical, safety-critical or contractual decisions.