In the series 3 episode The Sound of Drums after The Doctor, Martha, and Captain Jack are declared public enemy number one, the Doctor uses parts from Martha's laptop and three TARDIS keys to create three "perception filter" necklaces so they can move about unnoticed.

That's three keys he had on him. I seem to remember something from Series 1 where losing the key was a big deal. Do other episodes suggest how many spare keys he's made?

How many TARDIS keys does the Doctor carry on his person? How many are in the TARDIS?

  • 16
    As many as the plot requires, of course.
    – Jeff
    Nov 28, 2011 at 22:45
  • 1
    Life is so much easier now that he (and Clara) can just "snap it open."
    – sipp
    Oct 8, 2014 at 18:19
  • 1
    I would hope that someone hundreds of years old would know to always keep a spare in their wallet.
    – Joe L.
    Oct 9, 2014 at 0:23
  • 1
    In the TV movie the Doctor says there is "a spare in a cubby hole above the P" of the TARDIS sign. I'm not sure if he ever replaced it, or if it's still the after the recent TARDIS regenerations. Aug 10, 2015 at 7:38

6 Answers 6


I don't believe it's ever explicitly specified how many keys to the TARDIS the Doctor carries, or for that matter, how many there are at all.

That said,

  • In Blink, there's at least one key that has been taken by Sally Sparrow that I don't believe is ever returned to the Doctor (unless it was in the package that Sally gave to the Doctor).
  • The Doctor makes a habit of giving keys to his companions.
  • The TARDIS has been seen to create new sonic screwdrivers for the Doctor. Presumably, it has the ability to create an infinite number of keys as well.

I don't recall the series 1 episode you mention, but assuming that you're right, it makes sense for the Doctor to have started carrying multiple keys just to prevent that from happening again. On the other side, he probably wants to be aware when he loses one so that he can "recode" the TARDIS door lock to not accept that key anymore (beware Weeping Angels), so he probably carries around 5. Even though that's a completely wild and random guess.

As for total TARDIS keys, I would say that besides the ones the Doctor gives out and those that he personally carries, there probably aren't any others since the TARDIS can probably create new ones on demand and just leaving them lying around probably creates huge security risks.

  • Ironically, it's been shown to be a standard, Yale type lock -- Adric used to pick it regularly, with the pin that held a medal to a shirt. Perhaps the tardis is simply able to 'clench' it's lock when it doesn't want to let someone in.
    – K-H-W
    Nov 28, 2011 at 23:38
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    Oh, and the Dr. Who Wiki has a list of known keys for it: tardis.wikia.com/wiki/TARDIS_key
    – K-H-W
    Nov 28, 2011 at 23:45
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    "As for total TARDIS keys, I would say that besides the ones the Doctor gives out and those that he personally carries, there probably aren't any others since the TARDIS can probably create new ones on demand and just leaving them lying around probably creates huge security risks." NOPE we know for certain because of Clara's episode where she steals all the spares that there are spares inside the TARDIS Apr 12, 2018 at 19:00
  • There's the right answer, below: eight keys according to Dark Water (Series 8 finale).
    – tilley31
    Apr 12, 2018 at 19:55

There are 8 keys, as far as I remember. Clara removed all keys the Doctor had hidden in the TARDIS in Dark Water.


It's never been clear how many TARDIS keys have been made over the course of the show (either the old or new show). Assuming The Doctor provided a key to every companion who's been on the show, then the total amount of keys would be in the mid forties, going by the list on wikipedia. The keys were almost certainly destroyed or given back, though, depending on if the companion died or simply left.

The danger of losing the key isn't really tied to a limited number of keys, but rather, if a key were to fall into the "wrong hands", then the TARDIS could be used for evil.

The amount of keys really fluctuates depending on the mood of the writer, and the overall state of the show. In some of the earlier serials, The Doctor and Susan were the only ones who had keys, and Barbera and Ian had to rely on someone else if they wanted to get back into the TARDIS. That was eventually changed to where everyone was given a key (or the TARDIS was simply left unlocked during an adventure). Generally, the key, when it's referenced, exists to point out that the companion is now a trusted companion of The Doctor.


No, there was his key, Martha's key and Jack's key. We even saw Jack give his key to the Doctor! The Doctor then apparently still only carries one key around himself.


As many as he needs, because he can just get another one out of his transdimensional pockets.


I am fairly certain that all three keys did not come from the Doctor. By this point, Martha Jones had her own key...

So that's one from the Doctor and one from Martha Jones.

And I believe I recall Jack fumbling to get his off a key ring.

So the answer isn't that the Doctor carries 3 keys or more.

It's that he carries ONE.

But as to how many copies he has, that's at least a little established in the episode where Clara steals them all and destroys them all, in a shared dream sequence. By all, I mean all that Clara knows about, which means there are likely a few more. Of course by this time, he just needs to snap to get in, but I guess that she doesn't know that...I can't find clips for either of these but the episode Dark Water and The Sound of Drums will show you what you want at least a little.

It is never actually established as to how many exactly he has made, or how many he generally carries. I am thinking that it has to be ONE as far as carries, because it's a very valuable thing to be carrying around. And again, when he's lost it, it's been a big deal.

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