<p>The vast majority of the time, none of the 2^32 possible nonces in a particular block header template will result in the header having a hash that meets the proof-of-work target.  In fact, the probability that this <em>doesn't</em> happen equals exactly 1 over the network difficulty.  Right now, that is 1/6,379,265,451,411.</p>

<p>When no nonce succeeds, one must change something else in the block header and start again.  The typical solution is to change the <em>extranonce</em> field in the coinbase transaction and recompute the Merkle root.  See <a href="https://bitcoin.stackexchange.com/questions/5048/what-is-the-extranonce">What is the extraNonce?</a></p>

CC BY-SA 4.0
2019-04-15T02:13:34.467Z
2019-04-15T02:13:34.467Z
Nate Eldredge
<p>I want to know why mining of nonce is difficult? </p>

<p>The nonce is 32 bits (4294967296) and a high level Nvidia graphic card can check and mine it in a second.</p>

<p>why do we need a pool to mine a blockchain?</p>

<blockchain><blockchain.info><ethereum>
If the nonce is 32 bits why the proof of it is difficult?
M.Binsonek
# If the nonce is 32 bits why the proof of it is difficult?

(Asked by: username_0 on 2019-04-15)

I want to know why mining of nonce is difficult?

The nonce is 32 bits (4294967296) and a high level Nvidia graphic card can check and mine it in a second.

why do we need a pool to mine a blockchain?

**Tags:** blockchain, blockchain.info, ethereum


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## 1 answers

### Answer by username_1 on 2019-04-15. Score: 8 | Accepted answer

The vast majority of the time, none of the 2^32 possible nonces in a particular block header template will result in the header having a hash that meets the proof-of-work target. In fact, the probability that this *doesn't* happen equals exactly 1 over the network difficulty. Right now, that is 1/6,379,265,451,411.

When no nonce succeeds, one must change something else in the block header and start again. The typical solution is to change the *extranonce* field in the coinbase transaction and recompute the Merkle root. See [What is the extraNonce?](https://bitcoin.stackexchange.com/questions/5048/what-is-the-extranonce)


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