Throughout the Dr. Who series, the doctors have claimed to be hundreds, even thousands of years old, (the tenth and eleventh both claim to be around 900, but throughout the series, eleven jumps into the thousands, even though its only been a few years for his companions, and now the 12th claims to be 2,000) but in relation to what? He is constantly jumping around through time, making it difficult to track. Does he claim his age to be in relation to Gallifrey as if he hadn't left or it hadn't been burned, (or saved, it's all too timey-wimey for me to make sense of) or does he simply not know?

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    I find it difficult to believe he isn't reasonably confident about his own age.
    – Valorum
    Aug 9, 2014 at 13:33
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    This begs going into Special Relativity... The age of something doesn't need to be in relation to anything - it can simply be the amount of time that object has experienced. Therefore if the Doctor wore a watch his entire life that would tell his age correctly as it has travelled with him - but since the Doctor doesn't there is no way he knows his exact age unless he can somehow read it from his own internal "body clock".
    – Kvothe
    Aug 9, 2014 at 14:20
  • In relation to "Tardis Mean Time" ( joke - not canon) Aug 9, 2014 at 17:42
  • The sixth Doctor also said he was 900 years old. If he does know how old he is, an in-universe answer might be that he is using local time (i.e. years of whatever planet he's on) sometimes, or that the automatic translator translates his speech into the local time system of whoever he's talking to, no matter what planet they're on.
    – Mr Lister
    Aug 10, 2014 at 11:47

1 Answer 1


Welcome to Doctor Who - full of inconsistencies.

This question is discussed here. Here's the theory subscribed to by the executive producer and scriptwriter:

"He has no clue"

A simple and self-evident theory is that the Doctor doesn't know how old he is because he has lost count, constantly travelling backward and forward through time making it difficult to measure one's lifespan at all. This theory began as fanon, with the Doctor occasionally admitting to being unsure of his age in spinoff media (COMIC: Doctor Who and the Time Witch, PROSE: Vampire Science); eventually it became solidified as canon in a televised story. (TV: The Day of the Doctor), although the War Doctor's immediate response suggesting he was 400 years younger than the Eleventh complicates matters.

This is the theory subscribed to by Doctor Who's current executive producer and head writer Steven Moffat in an interview with SFX:

“The thing I keep banging on about is that he doesn't know what age he is. He's lying. How could he know, unless he's marking it on a wall? He could be 8,000 years old, he could be a million. He has no clue. The calendar will give him no clues." - Steven Moffat, SFX, May 2010

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