Fun with math! Sort of.
Throughout the history of Doctor Who, the Time Lord has been known to hand out his age willy-nilly, almost as though he enjoys answering such a typically delicate question. But what is the true number? Can it really be calculated, or must it always be a lie? Who wants to play a numbers game?
Note: For the sake of keeping the record as clean as possible (which is basically impossible), only the television show will be considered for canonical references to age. Some suggestions from the audio plays, books, and comics might be considered for filling in knowledge gaps, but not taken as “gospel.”
During the tenure of Classic Who, there was a definite attempt to keep the Doctor’s age roughly consistent in the canon. He entered the Time Lord Academy around the age of eight, finished primary school at 45, and saw the Medusa Cascade when he was “just a kid” at age 90. Question is—when did he nab his TARDIS and start touring the universe?
According to Romana (who one would assume to be right about such things, though Rassilon knows how she manages it), the Fourth Doctor had been traveling in the TARDIS for 523 years when he was 759. If that’s the case, some quick subtraction tells us that the Doctor stole the TARDIS at the tender age of 236-ish. Does this stack up with everything else the show tells us?
So far, so good. The First Doctor regenerated at about 450 years old, which is supported again by the Second Doctor when he gives his age to companion Victoria in “The Tomb of the Cybermen.” The Third Doctor was known to be a bit deceitful about his age (he almost claims to have been a scientist for several thousand years to the Master’s assistant, Professor Kettering), but it’s said in “Planet of the Spiders” that he regenerated at the age of 748.
This goes on to be supported by the Fourth Doctor, who claimed to be around 750 while he was traveling with Sarah Jane and Leela. He then claimed to be 756 when he met Romana, but she corrected him to 759. (We might assume that the Doctor had a bit of a crush and knocked off those three years to seem younger…) By the time he regenerated into the Fifth Doctor, the age was bumped up to 813, suggesting that the Doctor traveled with Romana for a fair amount of time before taking on Adric, then Nyssa and Tegan.
Okay, this is where it will start to get more confusing for New-Who-only fans. The Sixth Doctor claimed to be 900 years old during his travels with Peri. The Seventh Doctor tells Melanie Bush that he’s the same age as the Rani, his old classmate—953—on his first outing. Then the timeline gets fuzzy. According to the 1996 film, the Seventh Doctor was nearing regeneration (due to old age) before getting shot and regenerating into the Eighth Doctor. We know that the Eighth Doctor aged somewhat before regenerating into the War Doctor, who also aged in that body—his reflection following the Eighth Doctor’s transformation is considerably younger than the man we see in “The Day of the Doctor.”
The Ninth Doctor arrives on the scene. When he first mentions his age to Rose, it’s in context of a rude awakening from Jackie Tyler: “900 years of time and space and I’ve never been slapped by someone’s mother.” Now, by this wording, one could assume that the Doctor means that he’s been traveling in the TARDIS for 900 years, which would make him over 1100. Rose clarifies that he’s 900 years old, which he agrees with, but that might be a deliberate mislead—since Rose seems to agree that 900 years is a big age gap, as her mother suggested, it makes sense that the Doctor wouldn’t then want to correct her with “Well, it’s actually more like 1123…”
The place where the numbers get well and truly borked is during Ten’s grandiose “Voyage of the Damned” speech. He Clint-Eastwoods it up in epic fashion—I’m the Doctor. I’m a Time Lord. I’m from the planet Gallifrey in the constellation of Kasterborous. I’m 903 years old, and I’m the man who’s gonna save your lives, and all six billion people on the planet below. You got a problem with that?
903. We could have glossed over it, just said it worked, that the Ninth Doctor really did mean 900 years aboard the TARDIS, but then the Tenth Doctor says the magic number—903—and the show pushes on from there. He’s 904 in “The Day of the Doctor,” 906 before regenerating in “The End of Time.” The Eleventh Doctor claims to be 907 during his early adventures with Amy, then goes on a 200-year-long farewell tour when he believes he’s going to die during the Impossible Astronaut plot line. By the time we hit “A Town Called Mercy,” he says he’s 1200.
In the Eleventh Doctor’s final episode, “The Time of the Doctor,” he tells Clara that he has been defending the people on Trenzalore for 300 years, making him at least 1500 years old. And then the Twelfth Doctor tells Clara that he’s over 2000 in at the end of “Deep Breath.”
It doesn’t add up even slightly, but here is a quote that Steven Moffat gave SFX in 2010 that might make sense of it all:
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.
While I’m a big fan of continuity porn, this really does make the most sense. Even with internal “Time Lord senses” that help him out with these sorts of things, knowing his own personal count of days would be impossibly hard to keep track of. There seem to be plenty of stretches where the Doctor travels on his own—how could he know then? When Clara asks him how long he’s been traveling alone in “Listen,” does he neglect to answer because he’s ashamed to say? Or that in combination with the fact that he simply can’t tell her for sure?
And if that’s the case… how old might he be?
To be clear, this is a completely arbitrary guessing game from this point on. It’s a fun exercise to point out just how old the Doctor could be, if all of these lives were given their due. Let’s say—for argument’s sake—that pretty much everything is correct through the end of the classic series. (This seems fair to do since his age is corroborated by Romana, another of his species.) If the Seventh Doctor goes from middle age to elderly in that body, one would assume that he’d occupied it for a least a couple hundred years, since the First Doctor’s body lasted 450 altogether before dying of old age. So the Seventh Doctor swapped out for the Eighth at around 1150. The Eighth Doctor ages, though not by much, so it seems likely that he could have been around for a century or so. That makes him 1250-ish when the War Doctor steps in. He appears to have aged quite a bit in that persona, so let’s say the poor guy is fighting that Time War for about 200 years. (Not a happy thing to suggest, but he seems weary enough.) We reach 1450, give or take.
The Ninth Doctor doesn’t get much time, as far as we know. His wounds seem too fresh and raw to have been around very long, and we know he doesn’t get too many days during his tenure with Rose and Jack (though it was likely longer than a year because it is time travel we’re talking about here). I’d give him 5-10 years max. Likewise with the Tenth Doctor, who burned out far too quickly. Maybe his little goodbye tour took longer than he believed and we can stretch his time to 15 years. So the Doctor is getting closer to 1500 at this point.
The Eleventh Doctor lives out his entire “life” in that body, which would probably give him a solid 400 years at least. If he got as much time as Moffat suggests, then he lived more like 600 years in that body, taking him to 2000+. Which is exactly where Twelve places himself, funny enough. So either way, the story seems to pan out. Just not with the numbers as and when they’re given.
Of course, the Doctor could be making it all up. Most of those numbers could be diminished or inflated at will. He might have accidentally started counting weeks as days at a certain point. Or counting seconds as minutes. Or maybe he means Gallifreyan years sometimes and those are only half as long as Earth years. Either way, it’s clear that one good reason for having a companion is to remind him to consider time a bit more carefully. And who knows?—he really might be 8000, for all that we can tell.