Light-year
A light-year was a unit of measurement used to measure interstellar distance. It was quantified as the distance that light travelled in a vacuum over the course of an Earth year. 100 light-years made up a light-century. (TV: The Ribos Operation)
Known distances
From Earth
Planet XXX was 9.2 light years from Earth. (AUDIO: Through the Ruins)
Epsilon Eridani was "about 11 light-years or so" from Earth. (COMIC: Is Anyone There?)
A colony planet visited by the Twelfth Doctor and Bill was 20 light-years from Earth. (TV: Smile)
Vega 3 was 27 light-years from Earth. (PROSE: K9 and the Beasts of Vega)
Arcturus was 40 light-years from Earth. (PROSE: Only a Matter of Time)
Aldebaran II was 65 light-years from Earth. (AUDIO: The Paradise of Death)
Halcyon was 90 light-years from Earth. (AUDIO: The Resurrection of Mars)
Sunday was 100 light-years from Earth. (PROSE: Wetworld)
Beta Caprisis was 100 light-years from Earth. (PROSE: Sanctuary)
In 1873, Mondas was 200 light-years from Earth. (AUDIO: The Silver Turk)
Bellatrix was 324 light years away from Earth. (PROSE: Nightshade)
Gger was 500 light-years from Earth. (PROSE: Listen - The Stars)
Crimson Heart was 10,000 light-years from Earth. (TV: Death of the Doctor)
The Orpheus constellation was 10,000 light-years from Earth. (TV: Aeolian)
According to one account, Gallifrey was 30,000 light-years from Earth. (PROSE: The Devil Goblins from Neptune)
The homeworld of the Uvodni, located in the Spiral Cluster of the Dragon Nebula, was 34,000 light-years from Earth. (TV: Warriors of Kudlak)
New Earth was 50,000 light-years from Earth. (TV: Gridlock)
Vandos was 60,000 light-years from Earth. (COMIC: Mr Nobody)
Dæmos was 60,000 light-years from Earth. (TV: The Dæmons)
Galaxy Seven was 290,000 light-years from Earth. (PROSE: The Eyeless)
Surobos was 420,000 light-years from Earth. (COMIC: Shipwreck!)
Gorgos was 100,000,000 light-years from Earth. (TV: Eye of the Gorgon)
According to one account, Gallifrey was 250,000,000 light-years from Earth. (TV: Doctor Who)
According to the Eleventh Doctor, Apalapucia was 2,000,000,000 light-years from Earth. (TV: The Girl Who Waited)
According to the First Doctor, Destination was billions of light-years away from Earth. (AUDIO: The Destination Wars)
From other locations
The Ao constellation and Qqaba were 9.6 light-years from Gallifrey. (PROSE: Lungbarrow)
Ribos was 300 light-years from the Magellanic Clouds. (TV: The Ribos Operation)
The Twelfth Cyber Legion was 20,000 light-years from Demons Run. (TV: A Good Man Goes to War)
Safeplace was about 32,000 light-years from Mars. (AUDIO: The Judgement of Isskar)
The Second Doctor once dematerialised the TARDIS while it was 4 quadrillion light-years from the nearest galaxy. (PROSE: When Starlight Grows Cold)
Katura was 3.62 light-years from Mars. (AUDIO: Judoon in Chains)
Known measurements
The Mutter's Spiral galaxy was around 100,000 light-years in diameter. (PROSE: The Eyeless)
The Morestran empire spanned 80,000,000 light-years. (PROSE: Zeta Major)
