12 (number)

12 was a number.

According to Jo Grant, 108 divided by 9 was 12. Also according to her, 12 divided by 4 was 3. (TV: The Claws of Axos)

Clocks generally showed twelve hours. (TV: Doctor Who, The Time of the Doctor, The Pyramid at the End of the World) As a result, there was 12 o'clock midday, (TV: Children of Earth: Day Five, The Gathering) also called 12 PM (TV: The Mind of Evil) or noon, bringing in the afternoon, (TV: Robot of Sherwood) and 12 o'clock midnight, (TV: Doctor Who) which ushered in the next day of the year. (TV: The Next Doctor, The Snowmen)

Earth years also had twelve months. (TV: World War Three, Last of the Time Lords) As a result, the Ninth Doctor once accidentally brought Rose Tyler back home to London twelve months too late, rather than twelve hours after departing, as intended. (TV: Aliens of London)

Skaro was the twelfth planet in its star system. (TV: "The Ambush")

The planet Tiro had twelve stars. (PROSE: Terror on Tiro)

Roberta Tovey was 12 years old, but "seemed much younger", in 2065. (PROSE: Lady Penelope Investigates the stars of the Sensational new film Dr. Who and the Daleks!) Nicky was twelve years old. (PROSE: Lonely)

Kaled mutants had twelve tentacles, which meant the Daleks primarily used a duodecimal counting system (as opposed to base 10 used by certain groups of humans, due to their ten fingers). (COMIC: The Organ Grinder)

The Eleventh Doctor, soon after regeneration, returned to Amelia Pond twelve years too late. (TV: The Eleventh Hour)

Time Lords were allotted twelve regenerations in a life cycle. (TV: The Deadly Assassin)

At the fall of Gallifrey, the Eleventh General believed that "all twelve" incarnations of the Doctor had appeared, remarking that he "didn't know when [he] was well off." He was corrected by Androgar, who revealed that they numbered "all thirteen". (TV: The Day of the Doctor)

After 300 years defending Trenzalore and being reunited with Clara Oswald, the Doctor discussed his regeneration cycle. He told Clara that he could change twelve times, for thirteen versions of himself. Clara called him "Number Eleven", but the Doctor reminded her of the "War Doctor". She renumbered him "Number Twelve". (TV: The Time of the Doctor)

When the Twelfth Doctor asked Clara Oswald to pick a two-digit number, she chose 12. He then asked the crew of the arctic base to look at the first word of page 12 of the book they were holding, as part of the Helman-Ziegler test. (TV: Last Christmas)

While trapped in his confession dial for 4.5 billion years, (TV: Hell Bent) the Twelfth Doctor left a message for himself to find room 12, and continually found his way there. That room contained an azbantium wall to Gallifrey, which he punched over and over again before dying to teleport himself back in. (TV: Heaven Sent)

The Twelfth Doctor once told Bill that "eleven plus two" was an anagram of "twelve plus one", to which Bill responded that both of these were equal to 13. (COMIC: Harvest of the Daleks)

On 23 July 1794, the TARDIS materialised twelve kilometres from Paris. (TV: "A Land of Fear")

James Clark Maxwell's investigations into electromagnetism took place twelve years prior to 1866. (TV: The Evil of the Daleks)

Susie Cabina was twelve years old when she was raped and murdered by Oswald Danes. (TV: The New World)

The Citadel of the Fleet was twelve kilometres in height. (PROSE: The Secret in Vault 13)

Information from invalid sources
The box of a pizza which Yasmin Khan ate with two of her friends was marked as 12". (NOTVALID: The Universe is Calling)