Convert between light-years, parsecs, astronomical units and kilometres, with light travel time thrown in.
1 parsec = 3.2616 light-years = 206,265 AU. 1 light-year = 9.4607 trillion km. 1 AU (Earth-Sun distance) = 149.6 million km ≈ 8.3 light-minutes. IAU 2012/2015 exact definitions.
The distance light travels in a Julian year: about 9.46 trillion km (5.88 trillion miles), or 63,241 AU. The nearest star system, Alpha Centauri, is about 4.25 light-years away.
The distance at which 1 AU subtends one arcsecond of parallax: 3.2616 light-years or about 30.86 trillion km. Astronomers prefer parsecs because parallax is how nearby distances are actually measured.
The mean Earth-Sun distance, defined as exactly 149,597,870.7 km. Light covers it in about 8.3 minutes; the Solar System is conveniently measured in AU (Neptune orbits at about 30 AU).