How many centimeters are in a light-year?

1 ly is about 9.4607 × 10¹⁷ cm, which is 946,073,047,258,080,000 cm under this calculator's definition. That is 9,460,730,472,580,800 m multiplied by 100.

Is a light-year a measure of time or distance?

A light-year measures distance. It is how far light travels in vacuum in one year, about 9.4607 × 10¹⁵ m.

How do I write 2 light-years in centimeters?

2 ly is about 1.8921 × 10¹⁸ cm. Scientific notation keeps the 19-digit number readable.

Which year does the light-year here use?

It uses the Julian year of 365.25 days, each 86,400 seconds. Light covers 299,792,458 m per second in vacuum, which gives 9,460,730,472,580,800 m. See IAU and NASA/JPL.

Light Years to Centimeters Converter

Enter a value to instantly convert between length units.

From

Precision4 dp

1 Light Year = 9.4607e+17 Centimeter

Key Formulas

Centimeter → Inch

in = cm × 0.393701

Kilometer → Mile

mi = km × 0.621371

Foot → Meter

m = ft × 0.3048

Inch → Centimeter

cm = in × 2.54

Formula

cm = ly × (9460730472580800 / 0.01)

Converting light-years to centimeters multiplies by 9460730472580800 / 0.01, so 1 ly is 946,073,047,258,080,000 cm, about 9.46 × 10¹⁷ cm. This converter derives the light-year from a Julian year: 365.25 × 86400 × 299792458 = 9460730472580800 m. IAU recommendations give the Julian-year convention, and NASA/JPL parameters list the constants. Centimeters suit astrophysics written in CGS units, where distances appear as powers of ten. The centi- prefix is defined in the BIPM SI prefix table.

Source: IAU Julian-year convention and NASA/JPL parameters (derived light-year factor)

Reviewed by the Convert Calc editorial team · Last reviewed: 2026-10-06 · see our methodology

Frequently Asked Questions

Real-World Examples

One light-year written out in centimeters for scale.

1 ly = 946073047300000000 cm

A 2 light-year gap in centimeters.

2 ly = 1892146095000000000 cm

A physics exercise asking for 10 light-years in cm units.

10 ly = 9460730473000000000 cm

A 100 light-year radius expressed in CGS units.

100 ly = 94607304730000000000 cm

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