<p>Not every user running a full node keeps a local copy of the entire blockchain. Most users probably run their node in pruned mode, which means they only need a few gigabytes to store the UTXO set (a set of transaction outputs that could be spent in future transactions).</p>
<p>The reason this is safe is that a pruned node needs to actually download and validate the entire blockchain when initially synchronizing. However since the UTXO set is enough to validate new transactions and blocks, the blockchain itself can then be discarded.</p>

CC BY-SA 4.0
2021-09-09T12:05:26.033Z
2021-09-09T12:05:26.033Z
Vojtěch Strnad
<p>I am a beginner of Bitcoins.
I read <a href="https://bitcoin.stackexchange.com/questions/21939/how-much-space-does-the-blockchain-take-up-per-day-and-per-hour-when-running-bit">here</a> that the size of the blockchain is heavy HUNDREDS of gigabytes.
I also read that one of the reasons bitcoin is safe is that EVERY user keeps a local copy of the blockchain on his machine and it gets updated whenever there is a transaction.</p>
<p>However, it is unthinkable to keep terabytes of data on the pc. How does it actually work?</p>

CC BY-SA 4.0
2021-09-09T12:07:23.817Z
Possible duplicate of [Do I need to keep all blocks when running Bitcoin Core?](https://bitcoin.stackexchange.com/a/48729/5406)
Murch
<bitcoin-core><blockchain>
Space of Bitcoin Blockchain
claudio
# Space of Bitcoin Blockchain

(Asked by: username_0 on 2021-09-09)

I am a beginner of Bitcoins.
I read [here](https://bitcoin.stackexchange.com/questions/21939/how-much-space-does-the-blockchain-take-up-per-day-and-per-hour-when-running-bit) that the size of the blockchain is heavy HUNDREDS of gigabytes.
I also read that one of the reasons bitcoin is safe is that EVERY user keeps a local copy of the blockchain on his machine and it gets updated whenever there is a transaction.

However, it is unthinkable to keep terabytes of data on the pc. How does it actually work?

**Tags:** bitcoin-core, blockchain

> **Comments:**
> **username_1**: Possible duplicate of [Do I need to keep all blocks when running Bitcoin Core?](https://bitcoin.stackexchange.com/a/48729/5406)  

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## 1 answers

### Answer by username_2 on 2021-09-09. Score: 2

Not every user running a full node keeps a local copy of the entire blockchain. Most users probably run their node in pruned mode, which means they only need a few gigabytes to store the UTXO set (a set of transaction outputs that could be spent in future transactions).

The reason this is safe is that a pruned node needs to actually download and validate the entire blockchain when initially synchronizing. However since the UTXO set is enough to validate new transactions and blocks, the blockchain itself can then be discarded.


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