How old are Sherlock and Mycroft Holmes in the BBC Sherlock TV-Series? Do they have other brothers and/or sisters?

  • As referenced in His Last Vow there was at least one other brother. Jun 15, 2014 at 18:55
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    @MeatTrademark I'd correct that to "As hinted [...] there might have been".
    – Napoleon Wilson
    Jun 15, 2014 at 19:01
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    Related: movies.stackexchange.com/q/16645/49.
    – Napoleon Wilson
    Jun 15, 2014 at 19:08
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    @NapoleonWilson Mycroft said, "Don't be absurd. I'm not to given to outbursts of brotherly compassion. You know what happened to other one." Seems pretty straight-forward. Besides, it's too late to edit that comment. AND you beat me to posting that related question. Jun 15, 2014 at 19:08
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    I hope they don't say Moriarity is the third brother :/
    – Dredd
    Jun 16, 2014 at 14:24

3 Answers 3



For there is no reference in the show, one can only assume that they are the same age as the actors:

  • Sherlock: 34 in S1 (Benedict Cumberbatch, born in July 19, 1976)
  • Mycroft: 44 in S1 (Mark Gatiss, born in October 17, 1966)

If you are going with the canon, however:

  • Sherlock: 27 in S1 (In His Last Bow, which is set in 1914 Sherlock is described as "He was a tall, gaunt man of sixty, with clear-cut features" so he must be born around 1854 and he first met with Watson 1881)
  • Mycroft: 34 in S1 (In The Greek Interpreter Holmes tells Watson that Mycroft is "Seven years [his] senior")


As pointed out before the show makes a reference to "another one". So there is a possibilty that there is another Holmes brother. But at the end of S3, we can only guess.

According to the novels A.C.D. wrote, there is no other brother mentioned. But a possible explanation that there might be one, is given here:

Holmes once stated that his family were country squires, which means that the eldest brother would have to stay to manage the house. If Mycroft were the eldest then he couldn't play the role he does in four stories of the Sherlock Holmes canon, so Sherrinford frees them both. This position is strengthened by the fact that Mycroft's general position as a senior civil servant was a common choice among the younger sons of the gentry.

Since the series takes place in the 21th century, there is no need for the eldest brother to manage the house. This only leads us back to guessing ;)

  • I don't think that actors' age gives much. My favorite counterexample is The Vikings where Ernest Borgnine plays the father of Kirk Douglas' character. Douglas was two months older than Borgnine.
    – his
    Jun 18, 2014 at 10:02
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    Yes that's why I put the canon ages in. For we don't know how old exactly Sherlock is at the beginning of A Study In Pink (probably something in between 27 and 34), I think it is save to say that Mycroft is indeed 7 years older than him (what reason should Gatiss and Moffat have to change that fact?).
    – whitespace
    Jun 18, 2014 at 12:00
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    @whitespace You claim that Holmes met Watson in 1881 in the novels. Actually A Study In Scarlet only says that Watson was wounded at the Battle of Maiwand 22 July 1880 and met Holmes some uncertain time later. It may be possible that Holmes and Watson met in 1880. As I remember some Holmesian chronologies have Holmes and Watson meet in 1880, some in 1881. Sep 6, 2018 at 13:44
  • @M.A.Golding On the official site the year 1881 is given. See: arthurconandoyle.com/doctorwatson.html
    – whitespace
    Sep 24, 2018 at 16:01

Here is an answer with spoilers from the Series 4 episode The Final Problem (transcript).

JOHN: So there were three Holmes kids. What was the age gap?

MYCROFT: Seven years between myself and Sherlock, one year between Sherlock and Eurus.

JOHN: Middle child. Explains a lot.

So, in summary (more spoilers):

Mycroft is eldest by seven years, then Sherlock, then a sister Eurus - whose life is a dark family secret kept by Mycroft - a year younger than Sherlock. The actual age of any of the siblings is never stated.


Though there has never been a direct mention about Sherlock's or Mycroft's age, but in the episode The Empty Hearse, there is a slight reference.

SHERLOCK: I didn’t know you spoke Serbian.

MYCROFT: I didn’t, but the language has a Slavic root, frequent Turkish and German loan words. (He shrugs.) Took me a couple of hours.

SHERLOCK: Hmm – you’re slipping.

MYCROFT (smiling tightly): Middle age, brother mine. Comes to us all.

Regarding the third Holmes sibling, nothing has been made clear yet. Hope the coming seasons will reveal the mystery.

Source (Transcript) : Ariane DeVere

  • I don't see the reference. "Middle age, brother mine" just means "everyone hits middle age", not any reference to being a middle brother or anything like that.
    – Bobson
    Jun 20, 2017 at 17:45

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