I heard many times that Albert Einstein needed a lot of sleep. For example, this BBC article claims that he typically needed eleven hours of sleep:

People's sleep needs can differ significantly.

At the extreme, Margaret Thatcher managed on four hours of sleep a night while Albert Einstein needed 11.

Is there any reliable reference supporting this claim?

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    This is one of those claims that gets made every now and then and I've never seen it sourced except to say that he claimed to need the sleep himself. Commented Jan 27, 2012 at 21:05
  • This doesn't strike me as a very notable claim; in the sense that the claim itself isn't very note-worthy--not that the claim isn't made in a notable fashion. Who cares if he (or N% of the population) sleeps 11 hours per day? That might be more than average, but it's not an extraordinary amount of sleep. Now if we hear a claim that someone only sleeps 1 hour per day, or 22 hours per day, then that would be notable.
    – Flimzy
    Commented Jan 29, 2012 at 1:45
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    @Flimzy Einstein sleeping 10-11-12 hours is cited pretty much everywhere they want to "prove" that sleeping long is good for you, but there is never a credible source to support it.
    – Sklivvz
    Commented Feb 2, 2012 at 8:22
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    @Flimzy By no means its strange. Just it is repeated over and over without pointing to any reliable source. Commented Feb 2, 2012 at 10:21
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    @Sklivvz: well, it also makes the point that sleeping 4 hours is good for you, Margaret Thatcher did quite well, I reckon.
    – nico
    Commented Nov 25, 2012 at 20:48

1 Answer 1


Well, this is hardly definitive; however, I have not been able to find any quote that was attributed to Einstein concerning him sleeping 10-11 hours a day. Also, I have found no reference to it that gives any sort of citation as to where they arrived at that information. One example of this sort of behavior is the book Power Sleep. While it makes the claim that "Albert Einstein claimed he needed ten hours of sleep to function well," no citation or reference is given as to when Einstein claimed this. This book, however, is listed as a citation on at least one website: http://library.thinkquest.org/25553/english/basics/need/amount.shtml. Various other news outlets use the same information without citation like the linked BBC story in the question.

The only quote that I have found concerning sleep that is attributed to Einstein is on that goes, "We sleep 1/3 of our lives away." This would imply that he accepted the idea of sleeping 8 hours a day (8=24/3), but again, there is no citation.

All in all, what I can say with certainty is that the majority of references to Einstein's sleep are drawn from other secondary sources that themselves do not give any evidence for this being the case. Many of Einstein's letters are available, but I have not had the opportunity to pore through those.

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    You should provide a reference to the corpus of Einstein writings that you analysed. It's fine if you did not find any reference to the sentence, but it would make a difference whether you looked up say 10 of his quotes or all of his writings...
    – nico
    Commented Aug 9, 2013 at 16:00
  • Power Sleep has one of the many references that is uncited but this one is cited as evidence for Einstein's sleep patterns. As for the quotations, I was attempting to find someone who attributed an actual quotation about sleep to Einstein. I was unable, through the means currently at my disposal, to find one: ie web searches. As I mentioned before, I have not had the opportunity to pore through his actual letters.
    – WR Sroufe
    Commented Aug 9, 2013 at 16:27
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    I know I may seem annoyingly nitpicking, but my point is that your answer is not reproducible. Say I want to check that effectively those quotes do not appear amongst the ones you checked. If I don't know what you checked I cannot repeat the exact search you did, and thus cannot say whether your answer is true or not and what are the limitation of your answer.
    – nico
    Commented Aug 10, 2013 at 11:01

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