This article,

Human brain can store..

claims the memory has a capacity of around 1 petabyte or quadrillion bytes.

This other one,

What's the memory capacity of the human brain

claims the memory storage capacity is around 2,5 petabytes.

What's the memory capacity of the human brain? Or at least the most widely accepted estimate?

  • 1
    $\begingroup$ Actually, I havent. I've always been curious about the comparison between computers and brains. I had a course in neuronal networks (computing) in the university, and having to code and debugging in the past, you get to realize that human problems wont be fully understood until we can trace how the human brain works. So I always want to know more details about how advanced the knowledge of how the human brain process, store , use of energy, etc. is $\endgroup$
    – Pablo
    Sep 9, 2019 at 21:51
  • $\begingroup$ I've just read the meta page on duplicates and seen that they don't get deleted anyway so I'll delete my previous comment where I said that I thought you might have asked this after reading the original answer. Neuroscience is quite different from computer science in that we really don't know how memory works. All we have are theories that are constantly competing and evolving. Forest's comment on the original question is a good response to this question. $\endgroup$
    – PCS
    Sep 9, 2019 at 21:59

1 Answer 1


I don't know the answer to your question but I'm not aware of anyone who does.

The paper referred to in the first article above is Bartol et al. (2015) in eLife (https://cdn.elifesciences.org/articles/10778/elife-10778-v2.pdf). This paper is a proposal of how one might estimate the storage capacity of a synapse. Their current estimate is 4.7 bits per synapse. The article states that more work is needed to get an accurate estimate. The paper does not provide a definitive answer to your question. There is not much research on this subject at the moment, probably because there are still many things we don't yet know about the nature of memory. In time we may find that a completely different method to Bartol's gives a better estimate.

The figure of 1 petabyte is not given in Bartol's paper. This value may have been given in the press release or it could have been calculated by the journalist (by multiplying the estimated synapse capacity by an estimated number of synapses). The estimate of the number of synapses in the brain is the subject of research itself. Bartol's paper says that there are 'many trillions of synapses', which doesn't give us enough information to calculate. The figure needed to get 1 petabyte is around 200 trillion synapses, if my maths is to be trusted. The figure of 1 petabyte is the product of two estimates that may or may not be right, so it's probably not reliable.

The second article is a Professor's response to this question. He says, in essence, that we don't yet know the answer and it would be difficult to calculate.

We still have so much to learn about memory. I suspect it will be some time before we know the answer to your question.

  • $\begingroup$ This is a nice factsheet about synapses - dana.org/uploadedFiles/BAW/Brain%20Brief_Synapse_Final.pdf. The figure on the factsheet of 86 billion neurons is often cited. It comes from Azevedo et al. (2009; doi.org/10.1002/cne.21974) and is a good starting point. Researchers are still working on this though so the estimate will be updated in new publications. $\endgroup$
    – PCS
    Sep 9, 2019 at 16:59

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