<p>The main reason to run Bitcoin-Qt is to help the bitcoin network by relaying transactions and blocks as well as verifying the blockchain.  Bitcoin is a distributed protocol and relies on its users for validation.  You can <a href="https://bitcoin.stackexchange.com/questions/11592/is-there-a-newer-bitcoin-blockchain-download-available">download</a> an initial blockchain so that your client doesn't need to get it from a peer node (your download will be limited by the upload bandwidth of the peer node).  Once synchronized, the network load is around 144 MBytes/day depending on the number of connections and the needs of your peer nodes (your upload bandwidth can be saturated for hours if another node needs to download the blockchain from you).</p>

<p>That said, if you just want to use bitcoins without participating in the network, you should use a light client such as Multibit, Electrum, or Armory.  Check <a href="http://bitcoin.org/en/choose-your-wallet" rel="nofollow noreferrer">here</a> for more information.</p>

CC BY-SA 3.0
2013-12-07T20:44:19.280Z
Considering Bitcoin-Qt participating in the network, does it mean it could act such a miner and collect some bit coins? What is the main difference between Bitcoin-Qt and a miner application?
Zag zag..
CC BY-SA 3.0
2013-12-07T22:18:26.303Z
The miner application (BFGMiner, etc) communicates with the local bitcoin client using the RPC interface.  The bitcoin client provides the block to be solved to the miner.   The miner does the hashing until it gets a solution and then tells the bitcoin client.  The client then broadcasts the block to the network.
ScripterRon
CC BY-SA 3.0
2013-12-07T16:22:56.187Z
2013-12-07T16:22:56.187Z
2017-04-13T12:47:34.187Z
ScripterRon
<p>It is a good question.  Bitcoin-Qt was the first client written.   It was written to download the entire blockchain, which is probably not optimal.</p>

<p>You are correct that this is problematic, and it will become even more so over time.</p>

<p>There are so-called thin clients, such as <a href="https://multibit.org/" rel="nofollow">MultiBit</a>, for instance, that you might want to look at.</p>

CC BY-SA 3.0
2013-12-07T16:57:26.540Z
This is not quite true. The client before Bitcoin-QT was called WxBitcoin. It is deprecated now.
Maciej Mączko
CC BY-SA 3.0
2017-05-03T17:30:38.210Z
I would not call this problematic, but the only way to grant real crypto security.
LukeLR
CC BY-SA 3.0
2013-12-07T15:46:29.077Z
2013-12-07T15:46:29.077Z
zkilnbqi
<p>I recently installed <em>Bitcoin-Qt</em> on my laptop and it started performing the synchronisation with the network since a couple of weeks. And it's not finished.</p>

<p>Why do the Bitcoin-Qt application have to do so? If I am right, this application is just a Bitcoin client... I mean, it have not to check transaction integrity such as a miner, right?</p>

<p>Also, I would know if according to you, in 10 years (with some imaginations), having a lot of transaction every days, this synchronisation could take some months or even more.</p>

<p>Thanks for your lights!</p>

CC BY-SA 3.0
2013-12-29T17:37:38.203Z
FYI, as of today, the full blockchain takes up ~16 GB of disk space.
Totor
<bitcoin-core><network>
Transaction history size
Zag zag..
# Transaction history size

(Asked by: username_0 on 2013-12-07)

I recently installed *Bitcoin-Qt* on my laptop and it started performing the synchronisation with the network since a couple of weeks. And it's not finished.

Why do the Bitcoin-Qt application have to do so? If I am right, this application is just a Bitcoin client... I mean, it have not to check transaction integrity such as a miner, right?

Also, I would know if according to you, in 10 years (with some imaginations), having a lot of transaction every days, this synchronisation could take some months or even more.

Thanks for your lights!

**Tags:** bitcoin-core, network

> **Comments:**
> **username_1**: FYI, as of today, the full blockchain takes up ~16 GB of disk space.  

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## 2 answers

### Answer by username_2 on 2013-12-07. Score: 1 | Accepted answer

The main reason to run Bitcoin-Qt is to help the bitcoin network by relaying transactions and blocks as well as verifying the blockchain. Bitcoin is a distributed protocol and relies on its users for validation. You can [download](https://bitcoin.stackexchange.com/questions/11592/is-there-a-newer-bitcoin-blockchain-download-available) an initial blockchain so that your client doesn't need to get it from a peer node (your download will be limited by the upload bandwidth of the peer node). Once synchronized, the network load is around 144 MBytes/day depending on the number of connections and the needs of your peer nodes (your upload bandwidth can be saturated for hours if another node needs to download the blockchain from you).

That said, if you just want to use bitcoins without participating in the network, you should use a light client such as Multibit, Electrum, or Armory. Check [here](http://bitcoin.org/en/choose-your-wallet) for more information.

> **Comments:**
> **username_0**: Considering Bitcoin-Qt participating in the network, does it mean it could act such a miner and collect some bit coins? What is the main difference between Bitcoin-Qt and a miner application?  
> **username_2**: The miner application (BFGMiner, etc) communicates with the local bitcoin client using the RPC interface.  The bitcoin client provides the block to be solved to the miner.   The miner does the hashing until it gets a solution and then tells the bitcoin client.  The client then broadcasts the block to the network.  

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### Answer by username_3 on 2013-12-07. Score: 0

It is a good question. Bitcoin-Qt was the first client written. It was written to download the entire blockchain, which is probably not optimal.

You are correct that this is problematic, and it will become even more so over time.

There are so-called thin clients, such as [MultiBit](https://multibit.org/), for instance, that you might want to look at.

> **Comments:**
> **username_4**: This is not quite true. The client before Bitcoin-QT was called WxBitcoin. It is deprecated now.  
> **username_5**: I would not call this problematic, but the only way to grant real crypto security.  

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