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    Distance & light

    Light-Year Converter

    Convert light-years to km, AU and parsecs.

    1 ly = c × 365.25 days = 9.4607 × 10¹⁵ m

    Inputs

    Results

    Kilometres
    9.46073 × 10^12 km
    Astronomical units
    63,241.1 AU
    Light-years
    1 light-years
    Parsecs
    0.306601 parsecs
    Light travel time
    365.3 days
    Worked solution
    1. 9.4607 × 10^15 m ÷ 1.496 × 10^11 = 63,241 AU
    2. 9.4607 × 10^15 m ÷ 9.4607 × 10^15 = 1 ly
    3. 9.4607 × 10^15 m ÷ 3.0857 × 10^16 = 0.3066 pc

    How it works

    A light-year is the distance light travels in one Julian year (365.25 days). It is a unit of distance, not time.

    Variables

    • AU — astronomical unit = 149,597,870,700 m
    • ly — light-year = 9,460,730,472,580,800 m
    • pc — parsec ≈ 3.0857 × 10¹⁶ m

    Assumptions and limits

    • IAU 2012 exact AU; light-year uses the Julian year (365.25 days)
    • Parsec defined as 648,000/π AU (IAU 2015 Resolution B2)

    For education only. These models are simplified and are not suitable for spacecraft navigation or safety-critical engineering. See our scientific accuracy policy.