# How much data can the human brain hold?

Last week I was listening to a really interesting radio programme, in which I heard a few facts that amazed me. Firstly, did you know that your brain has around one hundred billion (yes, 100,000,000,000) neurons. Each of those neurons are thought have tens of thousands of connections to other neurons. That means in your brain there are… a lot of connections!

Anyhow, in the radio show they also stated that a cubic millimetre of brain tissue contained a petabyte of data. Unless you know your bits and bytes, you might not realise what that means. To put it simply, one cubic millimetre of brain matter has the capacity to store all the digital images currently on Facebook, i.e. every image the social network has ever had uploaded. This is only possible thanks to the number of connections between brain cells.

All that in just one cubic millimetre of your brain! Gosh.

This got me thinking, how much data can the human brain hold? To start investigating this I first needed to brush up on my knowledge of storage units.

### Bits And Bytes

Okay, lets start from the beginning. The smallest packet of data you can get is a bit, which is equivalent to one binary digit. A byte is equivalent to 8 bits of data, therefore a bit is equal to 0.125 bytes. Make sense so far?

In between bit an byte is the less well known nibble, which is equivalent to 4 bits. I suspect whoever invented bits, nibbles and bytes was either a little obsessed with food, or quite peckish at the time!

The next step up from a byte is a kilobyte, which is equal to 1,000 bytes in terms of storage space. If you wanted to talk about processing ability, one kilobyte is equal to 1,024 bytes – lets stick to storage though!

1kB = 1,000 (one thousand) bytes

This is still really tiny. To put it into perspective the size of a typical 80 word plain text email is around 10kb (or 10,000 bytes) – source About.com.

From kilobytes we climb to megabytes which equal 1,000 kilobytes.

1MB = 1,000,000 (one million) bytes

On my digital camera, I have it set to the highest quality and image size to 3264 by 2448 which produces images usually between 2 and 5MB. Quite big relative to a kilobyte.

The megabyte has nothing on the gigabyte though, which is 1,000 megabytes!

1GB = 1,000,000,000 (one billion) bytes

The maximum any CD ROM can hold is 900 megabytes of data which is 100MB less than a gigabyte. So a gigabyte is just bigger than a CD.

After a gigabyte comes a 1,000 times bigger terabyte.

1TB = 1,000,000,000,000 (one trillion) bytes

In my current computer I have a terabyte sized hard disk. Many computers come with terabyte or half terabyte hard disks nowadays, however go back seven or eight years and 80gb (8% of a terabyte) was around the average hard disk size, showing the advancements that have been made in just a few years.

Eventually we reach the petabyte, and you guessed it, it is 1,000 times bigger again.

1PB = 1,000,000,000,000,000 (one quadrillion) bytes

One petabyte is the amount of data one cubic millimetre of brain tissue can hold. That’s two petanibbles and eight petabits.

### How Much Data Could A Brain Be?

There are so many factors which affect brain size that it is going to be hard for me to work this out with any sort of accuracy, but I will try. Ethnicity, gender and body size along with many other factors affect brain size. The amount of data the brain can store isn’t solely dependant on size, but lets ignore that for now. The average female brain is around 1130 cubic centimetres, whilst the average male brain is 1260 cubic centimetres. That said women have more connections between the two hemispheres than men do.

Averaging it out, that means that the average brain size is 1195 cm3. So how many cubic millimetres go into 1195 cm3? 1,195,000 – to be precise.

That means that the human brain can store 1,195,000 petabytes of data! That is equivalent to 1.195 zettabytes, as an zettabyte is equal to 1,000,000 petabytes.

### What Percentage Of The Brain Is Storage?

Not all of your brain is dedicated to storage though, meaning that 1.195 zettabytes isn’t true to the amount of data we can store. So, how much of the human brain is storage?

From my understanding, most memory processes and storage happens in the temporal lobe. This is approximately 25% of the brain – that is a very approximate percentage!

### How Much Data Can A Brain Hold?

In order to answer the above question, I am assuming that 25% of the brain is dedicated to memory, whilst the rest is required for other functioning, and that the average brain is 1,195,000 cubic millimetres in size.

25% of 1,195,000 cubic millimetres is 298,750 cubic millimetres. If one cubic millimetre of brain tissue contains a petabyte of data then the average human brain is able to hold 298,750 petabytes of data.

298,750 petabytes of data is equivalent to:

• 2,390,000,000,000,000,000,000 bits
• 298,750,000,000,000,000,000 bytes
• 298.750 exabytes (approx 300 exabytes)
• 0.29875 zettabytes (approx 0.3 zettabytes)

So there you have it, were you to max out your memory, you could probably store around 300 exabytes of data.

To put 300 exabytes into perspective, one standard single layer Blu-Ray disc can hold 25GB of data – approximately 5 hours of HD video. Therefore your brains memory could theoretically hold 12,000,000,000 Blu-Ray discs – around 60 billion hours of HD video!

Will we ever be able to technically match the amazing feats that nature has achieved? I am not so sure you know…

## 18 thoughts on “How much data can the human brain hold?”

1. Neil

Given the potential storage capacity it is surprising that we don’t make better use of it. I quite regularly forget some pretty basic things. Maybe we need better retrieval systems to be able to access all of that data.

I think we have all we need Neil, just we don’t maximise the potential. I think a lot of our brain can’t be controlled consciously, which means we are loosing out :-/

Wow. I never expected it to be quite so much. It’s quite hard to think of what all that storage space actually holds.
I suppose if you think back to the things you’ve done since you woke up this morning, you would be able to remember an impressive amount of it. And those memories would contain data relating to all the senses not only sight and hearing. You’d be able to remember what a particular object felt like, smelt like and tasted like. That’s a lot of data.

It is a lot of data! I found it a challenging but interesting article to write. It took me a long time, and I appreciate that my accuracy is probably relatively low but I enjoyed writing it, and it is good to here that it made for interesting reading too 🙂

3. Hey Christopher. Another intriguing post which kept me engrossed for the whole time.
I wish there was a way to store data in the brain since all my external hard disks are full and so will my laptop be soon. 😀 Our brain is truly fascinating !

There is a bit of an error in the data conversions or maybe you did it purposely not to make the numbers too confusing for the people who are new to bits and bytes:

“1kB = 1,000 (one thousand) bytes”

The actual conversion is 1 kB = 2^10 or 1024

Similarly, 1 MB = 1024 kB and so on.

You may have missed the line I wrote that explained the bytes conversion: “The next step up from a byte is a kilobyte, which is equal to 1,000 bytes in terms of storage space. If you wanted to talk about processing ability, one kilobyte is equal to 1,024 bytes – lets stick to storage though!”

Basically in terms of processing ability, bytes are measured differently to how they are measured in terms of storage space. As I the article is about storage, I used the conventional conversion.

4. Carley Verlingk

It is amazing how much data that we can actually hold, I love learning about these facts so this has been great to read, thank you for the share!

Good to know Carley, it is a great fact to know, that your brain can hold 12 billion Blu-Ray discs of data 🙂

Thanks for the comment, welcome to the blog!

5. Christa

0.3 Petabytes!!
I wish I could use 10% of this amount only, I would never have flunked in my examinations moreover, I’d be installing a multipurpose USB port with my brain so I could take a print out anytime or just transfer a movie while I’w be bored. 😉

I think a USB port would definitely be useful, however it does sound a little Sci-Fi!

Thanks for the comment Christa, welcome to the community 🙂

• Christa

The world what we see was Sci-Fi a few decades back Christopher. I hope it may come true some day so all our memory leakages could be resolved. 😉
Anyways thanks for a warm welcome.

6. Bruce

“Firstly, did you know that your brain has around one hundred billion (yes, 100,000,000,000) neurons.”

Actually, it’s 86 billion. I still hear 100 billion, even from some neuroscientists.

“Each of those neurons are thought have tens of thousands of connections to other neurons.”

Actually, it varies. Some neurons have tens of thousands of connections, some have thousands.

“Anyhow, in the radio show they also stated that a cubic millimetre of brain tissue contained a petabyte of data.”

That’s a misunderstanding of a Harvard/Microsoft research paper in which the authors estimated the amount of data required to image through electron microscopy all the synaptic circuitry in 1 cubic mm of brain. They estimated 1 petabyte would be required to store all the images — not the amount of data contained in that amount of brain tissue.

Since the rest of the calculations are based on the erroneous 1 petabyte factor, the conclusions in the article are incorrect. In any case, trying to calculate the “storage capacity” of the human brain is a fool’s game, since the brain doesn’t work like a computer with a hard drive. Data isn’t “stored” within neural connections, the neural connections are the data.

• Christopher Roberts

Hi Bruce, thank you for the comment.

I wasn’t trying to be very accurate, and I made a lot of very tenuous assumptions. I didn’t expect to get close, as I imagine the greatest minds with the greatest technology and resources would still struggle to get an accurate answer, however it was good fun trying.

Could I ask where you got your facts from. I am not disputing them, but you don’t give a source. I fully appreciate that facts are misquoted all the time, and tracking down the source of some facts (if they are indeed facts at all) can be very difficult.

Once again Bruce, thanks for the comment.
Christopher – Editor

I was thinking about all of the useless things i have memmorized, i wounder is there a way i can replace those useless files with something more beneficial and useful and be able to access that information as ez as i can remember lyrics from song i know back to 1986!

• Christopher Roberts

Hi Adil, from my understanding everything you do/think pushes other memories further and further back. Also, the more often you remember something, the more likely you are to slightly alter that memory and create a false account of what actually happened.

Christopher – Editor

8. Bhavna

I loved your post, this is exactly what I’ve been looking for. Thanks for explaining everything with basics.
I have more questions –

1. What is more, the information we encounter in lifetime or the full possible amount of info that brain can store? I know every person has to witnessed different amount of information, but I would like you to comment on it anyway 🙂

2.does brain contain pre stored information? What happens to information once we die?

3.is the storage capacity constant or its always changing according to age?

4.what is essentially the form of information in the brain? Are they dynamic signals always flowing through neurons OR the signals flow only during processing a memory and rest of the time stored as stationary unit inside some cell?

9. Anonymous

This is incorrect, actually the amount is closer to 500TB.
– 86 billion neurons – lets assume that to store their internal state each neuron requires 8 bits, thats 86GB for state of the neurons;
– 100 trillion synapses – each synapse could be considered having a source neuron and a destination neuron and some small piece of metadata. To describe a synapse emanating from a neuron, one would need the destination neuron id (37bits), and the metadata (8bits)

Therefore 86e9*(37+8)+100e12*(37+8)/8 = 566.37TB. With some compression (local connections, neuronal clusters, etc) it would be 10-15 times less just to store the compressed data of a human brain state on a computer.

If the popular-scientific understanding of the human connectome is correct, this would also mean not only that the human brain can store 500TB of data, but also that the “human brain” for consciousness purposes could be stored in a 50-500TB drive.