Is it true that The Doctor can only regenerate 12 times? Because if it is, the series won't last much longer. Matt Smith's Doctor is number 11 - that only leaves two more, right?

  • 1
    I don't know for sure if it was 12, I always thought it was 9, vaguely remember somebody talking about it when I was a kid. I do know the BBC has largely expidited the process for drama's sake and actors leaving the series too early, which has damaged the canon. Commented Jan 18, 2011 at 22:07
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    Like Starships crossing the galaxy, the count of regenerations move at the speed of plot. Commented Jan 18, 2011 at 22:46
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    Strange things happen after The Doctor's final regeneration... youtube.com/watch?v=Do-wDPoC6GM&NR&t=16m10s
    – GAThrawn
    Commented May 15, 2011 at 17:55
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    Do we even know that William Hartnell was the first incarnation? If so, then Patrick Troughton is the first regeneration, and Matt Smith is the tenth. Commented Dec 18, 2011 at 8:04
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    @luserdroog Yes; the fact that Hartnell was the first is referenced in many stories, including the Tenth Doctor christmas episode "The Next Doctor"
    – Nellius
    Commented Jan 25, 2012 at 11:48

20 Answers 20


After the release of series 8 and 9, this question is in need of an updated answer.

Firstly, the 12-regeneration limit is definitely still in canon and not Moffetconned. From the 2013 Christmas special:

CLARA: But you don't die. You change. You pop right back up with a new face.
DOCTOR: No, not for ever. I can change twelve times. Thirteen versions of me. Thirteen silly Doctors.
CLARA: Okay, so you're number eleven, so
DOCTOR: Ha. Are we forgetting Captain Grumpy, eh? I didn't call myself the Doctor during the Time War, but it was still a regeneration.
CLARA: Okay, so you're number twelve.
DOCTOR: Well, number ten once regenerated and kept the same face. I had vanity issues at the time. Twelve regenerations, Clara. I can't ever do it again.

-- The Time of the Doctor

Except that of course he does do it again, later on in the same episode, when the Time Lords grant him extra regenerations and he turns into a grumpy old Scotsman.

As of right now, the Doctor has an unknown but probably large and finite number of regenerations left available to him. In an episode of series 8, he says that he doesn't know how many and it could be infinite:

DOCTOR: Yes. She doesn't want to stand there watching us getting shot, does she? She'll be terrified. Girl first, then her teacher, and then me. You'll have to spend a lot of time shooting me because I will keep on regenerating.
(Courtney sits on the deck behind the big Russian bomb and sulks.)
DOCTOR: In fact, I'm not entirely sure that I won't keep on regenerating for ever.

-- Kill the Moon

But most recently, in the series 9 finale, the man who apparently actually gave him the extra regenerations, or at least was behind the decision to do so, makes it sound like he now has quite a lot but not infinitely many (although even he doesn't know how many):

RASSILON: A direct order of your President! You leave me no choice.
(Rassilon activates his gauntlet.)
RASSILON: How many regenerations did we grant you? I've got all night.
(Four gunships arrive.)

-- Hell Bent

(all emphases mine)

  • You asked me to change my accepted answer. Fair point - this answer contains new and relevant information so I have accepted it (at least until an even better answer appears :) ). Commented Jan 16, 2016 at 11:00
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    This answer is now outdated, again, due to more recent material.
    – Gnemlock
    Commented Oct 8, 2020 at 3:15

Here's what is supposedly the official word. From Doctor Who is now immortal, reveals the BBC: Edict that Time Lords can regenerate only 12 times before they die has been quietly ditched:

He travels through time and space, saves the Earth, and has millions of fans all over the world. But as every "Whovian" knows, the Doctor cannot last for ever: Time Lords are able to regenerate only 12 times before they die.

Fans have always thought that the 13th doctor would be the last, thanks to a 1976 Doctor Who episode, The Deadly Assassin, featuring Tom Baker as the Doctor in his fourth incarnation, and revealing for the first time the regeneration limit. But a passing comment in a children's television programme later this month is set to rewrite history and cast the Doctor, iconic hero of the world's most successful and longest-running science fiction series, as immortal.

In the Sarah Jane Adventures (yes, that was the old friend), in the episode "The Death of the Doctor". The Doctor is asked how many times he can regenerate, and replies

Five hundred and seven

Recently (always considering that in the Whoniverse the word "recently" is very flexible), Moffat stated he had a plan to skirt the regeneration issue.

  • 12
    To add just a bit of detail, the line was in the spin-off series "Sarah Jane Adventures" episode "The Death of the Doctor". He's asked how many times he can regenerate, and replies "five hundred and seven". My opinion is that it's fine to ditch the limit, but there should be some addressing of it...indicate that it was an artificial limit imposed by the Time Lords after Rassilon got out of control, or something. Commented Nov 16, 2011 at 21:22
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    @ChrisB.Behrens +1. There have been enough "hints" that the regeneration limit was artificially imposed that they should just come out and say it; it would have been perfect to have The Master comment on it at some point during Ten's run (about how with the Council gone there's nothing left to stop him from living forever, or some such.) Maybe they still will.
    – KutuluMike
    Commented Jun 4, 2012 at 21:08
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    I would like to point out that the Master has been granted new regenerations after his 12 'ran out'. 12 is the standard limit, but that does not stop more being granted.
    – Pharap
    Commented Nov 13, 2013 at 19:24
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    As the show has moved on and the canon has now shown this answer to be incorrect, can we get the accepted answer changed? Or, of course, this answer updated to include the new information...
    – Jules
    Commented Apr 20, 2014 at 11:38
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    It seems that the answers here have not been updated in a while. In the latest episode (at the time of writing this), 'The Time of the Doctor', he does mention that he has used up all 12 of his regenerations. But as mentioned, Moffat used this episode to 'skirt the regeneration issue' by giving him a reset for a whole new regeneration cycle. As an added bonus he also wraps up the plot line dealing with the Silence and Trenzalore. So, yeah the Doctor is Immortal. YAAAAAAY.
    – Suman Roy
    Commented Aug 9, 2014 at 11:06

This is Doctor Who we're talking about. These are the retcon experts. Asking Doctor Who to be internally consistent is equivalent to expecting Douglas Adams to be logical. Literally in some cases, since Douglas Adams wrote for Doctor Who for a while.

Believe me, if they wish to continue past Doctor 13, they will find a way. And it will make some sort of absurd, twisted sense. Or not, depending on the mood of the writer at the time.

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    Rule #1 explains everything: The doctor lies. Commented Oct 2, 2011 at 20:46

It has come up from time to time that the 12 regeneration limit may be some artificial, Time Lord Council imposed thing.

eg. In the Five Doctors, the council convinces the Master to help them out by offering to give him regeneration, as he had no regeneration energy left and was in the Trakenite body of Nyssa's father, Tremas.

From the wikipedia article:

"This is the first time it is suggested that a new cycle of regenerations can be bestowed on a person (in this case the Master), implying that it could be possible to circumvent the twelve-regeneration limit established in The Deadly Assassin."

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    Also, in the new series, it is mentioned that The Master was "reincarnated" by the Time Lords during the Time War; further supporting that hypothesis
    – Nellius
    Commented Jan 20, 2011 at 13:55

There have been three official canon answers:

Doctor Who Season 6 (1969), "The War Games": Indefinitely, "barring accidents".
Doctor Who Season 14 (1976), "The Deadly Assassin": 13.
The Sarah Jane Adventures Series 4 (2010), "Death of the Doctor": 507.

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    I think his answer in SJA was a joke, just something to say to stop the kids asking questions.
    – Adeptus
    Commented Sep 23, 2014 at 0:08
  • I agree with Adeptus because this would also mean that future regenerations could go back and look like a previous regeneration. Commented Apr 6, 2016 at 16:55

That rule comes from one story (if I recall correctly "The Deadly Assassin"). But it looks like the writers will change it if needed: http://www.radiotimes.com/blogs/1062-doctor-who-regenerate-immortal-12-times-13-lives/


First, we should establish the count of used regenerations. In the episode The Time of the Doctor, it's confirmed that the Doctor's Meta-Crisis regeneration did count as a regeneration. Between this regeneration, and the recently-revealed (Night of the Doctor/Day of the Doctor) 'War Doctor' regeneration, Matt Smith, who we previously called the 11th Doctor, was in fact the 13th regeneration of that character. The math works out that the original Doctor was his original face, so the 2nd Doctor is the 1st regeneration and so on. This then means that the 13th Doctor is his 12th and final natural regeneration.

However, just as they did for The Master, the Time Lords granted The Doctor a fresh set of regenerations (The Time of the Doctor). So as the '11th' regenerates, he turns into Peter Capaldi, the first of a new set of 12 regenerations. As of The Time of the Doctor, the Doctor now has 11 more regenerations left.

Largely copied from my answer on Movies & TV.SE

  • Why are you being so aggressive? Sigh. Just never mind. -1 because this answer contains, in my opinion, several contradictions leading to potentially false statements and you have outright refused to consider listening to me about them. Commented Jan 6, 2015 at 10:17

The average Time Lord can only regenerate 12 times - this has been pretty clearly stipulated in stories such as The Deadly Assassin and Mawdryn Undead, from the 70s and the 80s... no matter what the Doctor may flippantly say in, e.g., Death of the Doctor.

However, there are certainly precedents for cheating death beyond the 12th regeneration. The Master, in The Keeper of Traken, was in his final regeneration and resembled a decomposing corpse, but managed to steal the body of Nyssa's father Tremas and use a power called "the Source" to enter into a new cycle of regenerations. A few decades on, he's still going strong, in several new bodies.

It seems clearly that if the Doctor Who franchise is still going strong while the 13th actor is in the lead role, they will find some way of giving our hero his own new cycle of regenerations. It's Doctor Who - anything can, and usually does, happen!


To add to Ross's answer, there's this little exchange from Time of the Doctor:

The Doctor: Everything ends.

Clara: Except you. You pop right back up with a new face.

The Doctor: No, not forever. I can change 12 times, thirteen versions of me. Thirteen silly Doctors.

Clara: But you're the 11th Doctor

The Doctor: Are we forgetting Captain Grumpy? Eh? Now I didn't call myself the Doctor during the Time War, but it was still a regeneration.

Clara: Okay, so you're No. 12

The Doctor: Well No. 10 once regenerated and kept the same face. I had vanity issues at the time. 12 regenerations, Clara... I can't ever do it again. This is where I end up, this face... this version of me.

That was before he got his new regeneration cycle, so we don't really know how many he has this time.


In Series 12, this has been (apparently) retconned.

The Doctor is revealed (according to the Master) to be the Timeless Child in episode S12E10 The Timeless Children. The Timeless Child is the original source of regeneration for the Time Lords and can regenerate indefinitely (or an unknown number of times), while Time Lords were engineered specifically to only be able to regenerate 12 times maximum.

I added the (apparently), because the Master can at times be an unreliable narrator.

  • In this case, The Master didn't lie. Remember, The Doctor met another The Doctor and none of them remembered another. We even saw TARDIS. This proves memory wipe and at least one extra regeneration.
    – user931
    Commented Oct 8, 2020 at 4:12

Based on the recent episode "Let's Kill Hitler", we see River Song giving her remaining regeneration energy to save the Doctor's life, so that may have prolonged the regeneration limit. That's very plausible, considering in "Silence in the Libray"/"Forest of the Dead", River Song physically died. We now know that she can regenerate, but she didn't/wasn't able to. I believe, IMHO, she couldn't have regenerated because she gave it to the Doctor.

  • River Song said in Forest of the Dead that regeneration wasn't an option even for the Doctor: "It'll burn out both your hearts and don't think you'll regenerate!"
    – rems
    Commented Sep 22, 2011 at 14:55
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    The Forest of the Dead remark, however, pertained to simply THAT form of dying. Time Lords can be killed in ways that prevent regeneration, and that would have been one of them. That was established in "The Deadly Assassin" when the Master shot the President of the Time Lords. Commented Oct 3, 2011 at 14:29

Originally, the doctor has only 12 regenerations, but in the episode let's kill hitler, melody, who has already regenerated twice, gives the the doctor her 10 remaining regenerations, leving him with 22. He then gives her one when she breaks her arm, leaving him with 21 regenerations, 22 lives, and 11 more Doctors. That means we're only half way done with the doctor. At this rate, the show will end in 2063 at least, and by that time we may have ourselves a real doctor!

  • 1
    you forget that Melody had already regenerated twice, first from the little girl in the astronaut suit into the melody that grew up with Amy, and then again into River Song
    – childcat15
    Commented May 24, 2013 at 1:42
  • Did the Doctor give River a full regeneration, or just some? I was under the impression he just healed her hand, which would presumably be much less energy than to regenerate an entire body.
    – mskfisher
    Commented Dec 5, 2013 at 18:01

The 12 regenerations is an artificial limitation probably created by elder Time Lord hierarchies, who knows how long ago. Just watch The Five Doctors, in this story the Time Lords offer The Master a new set of regenerations.

Also, if he could only have 13 incarnations the Doctor would more than likely dire a very young man. The Time Lord lifespan is around 7000 years. The Doctor as far as we know is only around 1,100 years old, because of his lifestyle he's running through his regenerations at an astronomical pace. This always makes me wonder why in the world would NuWho Doctors always claim to be so old. Yes, to humans and most aliens he's old, but to his own people and what he sees as normal for Time Lords, he's a young'un.


I was always under the impression that The Doctor would have 12 regenerations. Like the hours on a clock. Hence *time*lord.


No one's mentioned Trial of a Time Lord, where the Master says that somewhere between around the "12th and final regeneration", the Doctor becomes the Valeyard and will seek to undo everything after Colin Baker.

  • But does that imply anything regarding the number of his regenerations? Commented Dec 17, 2011 at 20:20
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    @Wikis It depends on how you parse the sentence. The way he speaks it, it sounds to me like "twelfth and final" are both qualifying one instance of the word "regeneration". But it could be that "and final" refers to the-next-one-after 12. Written, of course, there's no indication of how far apart "12th" and "final" are. But it could be an indication of deduction on the Master's part: it must be after 12, because that's when a Time Lord would start to become desperate. ... In any case, it helps explain the darker turn in the Doctor's character of late. Commented Dec 18, 2011 at 7:04
  • Very good point! Commented Dec 18, 2011 at 7:39

In the latest series episode 'Let's kill Hitler', River poisoned him and he went into the Tardis and it said 'regeneration disabled'. I presumed that meant that he ran out of regenerations. And when River was in the hospital, I thought Amy said that she had used up ALL remaining regenerations to save him, not just the last of her energy. So I was under the impression that both River and the Doctor have no more regenerations left. But I'm probably wrong.

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    I thought this was meant as River giving the Doctor all her remaining regenerations, not using them up? I may also have misunderstood!
    – NiceOrc
    Commented Nov 17, 2011 at 1:46
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    It meant the poison disabled regeneration (Moffat confirmed it in a tweet), then River gave all of her regenerations to save him. Commented Nov 17, 2011 at 8:42
  • @Martha: Nah you're not wrong there, about the Judas Tree's poison disabling regeneration, but he couldn't regenerate anyway, because he's the 13th Doctor actually.
    – L.J Rob
    Commented Jan 5, 2015 at 22:31

River did give him the rest of her regeneration energy because she's going to the library anyway but not just that he told clyde that he has unlimited the show is so poplar they'll keep him going the doctor is a little energizer bunny he'll keep on going.

  • river didn't know she would go to the library in "lets kill hitler"...in fact that episode was "River" about as far away from he library as possible. and you cannot assume a 1-for-1 conversion of her remaining regenerations, as she gave them up to save the doctor's life. that probably ate a few up, and also we don't know what regeneration she was in before becomming river. at a minimum, "river" is her 3rd form (baby grew into little girl who regenerated just off screen, possibly into Mel, who regenerated into river), or she could have alot fewer remaining.
    – acolyte
    Commented May 23, 2013 at 19:15

In the audiobook "Ring Of Steel," the Doctor makes a comment about only being young twelve times.


According to the official Doctor Who Magazine, which I bought right after they announced Matt Smith, Timelords can only surpass the 12 regenerations if they do the time lord council a favor, and since the tenth doctor killed them all, he's out of luck. They probably will pull the "River gave up her regenerations" thing, but she did so to counter the poison.

  • 1
    Please provide a link to the article. A recollection may not be sufficient.
    – Solemnity
    Commented Mar 12, 2013 at 23:13
  • Doctor Who Magazine, while official, has no authority over what continuity in Doctor Who. here. it seems that they made mention of a scene in "The Five Doctors" where the High Council of Gallifrey bribe the Master into helping them with an offer of a new regeneration cycle.
    – Ria Byss
    Commented Sep 10, 2020 at 17:14

It is 13 regenerations. I got a book for Christmas, as I am completely obsessed. It says there can only be 13 but it is possible one can be forged through artificial means. However, these artificial means are most likely only found on guess which destroyed planet. I'm sure Moffat will come up with something, though, he always does. By the way, the fact of regeneration was not even there until Hartnell couldn't do the show anymore, by then the show was way too popular to cancel, they didn't think much of it when it first started, but then regeneration was an option. They made the 13 rule because anyone saying that the show would last 50 years would be put in a madhouse.

  • 2
    13 lives/incarnations, not regenerations. 12 regenerations, which gives a total of 13 different doctors (12 'generations plus the original)
    – acolyte
    Commented May 23, 2013 at 19:17

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