<p><a href="https://en.bitcoin.it/wiki/Nonce" rel="noreferrer">Nonce</a> is a 32 bit arbitrary random number that is typically used once. In Bitcoin's mining process, the goal is to find a hash below a target number which is calculated based on the difficulty. <br />
Proof of work in Bitcoin's mining takes an input consists of Merkle Root, timestamp, previous block hash and few other things plus a nonce which is completely random number. If the output results in hash is smaller than the target hash you win the block and the consensus is reached. <br />
You need to brute force all possible nonce in order to luckily find a hash smaller than the target hash. It could literally be any number between 0 and 2^31</p>

CC BY-SA 3.0
2017-12-04T16:48:22.927Z
But if the nonce is 32-bit, that is only 4 billion tries maximum, which is about a few minutes with a good nVidia card, right ? or is the speed much lower than that ?
Matt
CC BY-SA 3.0
2017-12-04T16:57:21.247Z
I think you forgot to talk about the extra nonce... and that answers my question above.
Matt
CC BY-SA 3.0
2017-12-05T15:51:21.623Z
There is no extra nonce. Your right. its a small number relatively but you have to remember the each second the timestamp changes new tx comes which changes the root and others so all accumulated plus nonce become a large set of options for miners.
abeikverdi
CC BY-SA 3.0
2017-12-05T19:32:14.210Z
Only a fixed set of tx are accepted when creating the block. And there is a max number of tx for a block. And please browse for extra nonce ;)    https://bitcoin.stackexchange.com/questions/32603/why-didnt-satoshi-make-the-nonce-space-larger
Matt
CC BY-SA 3.0
2017-05-21T15:31:53.680Z
2017-05-23T12:59:20.340Z
2017-05-23T12:59:20.340Z
abeikverdi
<p>Yet another info and info, <strong>NONCE</strong> stands for: <strong>N</strong>umber used <strong>ONCE</strong></p>

CC BY-SA 4.0
2023-08-30T16:43:04.483Z
This does not provide an answer to the question. Once you have sufficient [reputation](https://bitcoin.stackexchange.com/help/whats-reputation) you will be able to [comment on any post](https://bitcoin.stackexchange.com/help/privileges/comment); instead, [provide answers that don't require clarification from the asker](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead). - [From Review](/review/late-answers/90141)
Mercedes
CC BY-SA 4.0
2023-09-15T14:35:09.937Z
Note that “number used once” is a decent memory hook to remember how a nonce is used in cryptography but it’s not the source of the word. My understanding is that it derives etymologically from “for the once”. Nonces don’t have to be numbers.
Murch
CC BY-SA 4.0
2023-08-29T15:37:55.623Z
2023-08-29T15:37:55.623Z
Faruk Postacioglu
<p>Believe me or not, but I believe the answer is that the nonce helps make it difficult for each miner to solve a block.  Just as the difficulty readjusts every ten blocks and blocks are mined every ten minutes, based on the nonce and the difficulty?  Did I say that right?</p>

CC BY-SA 4.0
2023-06-09T03:32:15.233Z
2023-06-09T03:32:15.233Z
Thasthllfe
<p>When I see the block info on <a href="http://www.blockchain.info" rel="noreferrer">blockchain</a>, I see that there is a field named "nonce", I could not find any relevant information on web regarding what a nonce is. Please explain what a nonce is what is the purpose of it.</p>

CC BY-SA 3.0
2017-05-21T20:26:33.003Z
possible duplicate of [What does nonce mean?](https://bitcoin.stackexchange.com/q/10717/5406),  [When a block is “discovered” how is the nonce determined?](https://bitcoin.stackexchange.com/q/1290/5406), related: [What is a block?](https://bitcoin.stackexchange.com/q/35699/5406), [Can someone explain how the Bitcoin Blockchain works?](https://bitcoin.stackexchange.com/a/13347/5406)
Murch
<mining-theory><terminology><block-header><nonce>
What is a nonce?
GypsyCosmonaut
# What is a nonce?

(Asked by: username_0 on 2017-05-21)

When I see the block info on [blockchain](http://www.blockchain.info), I see that there is a field named "nonce", I could not find any relevant information on web regarding what a nonce is. Please explain what a nonce is what is the purpose of it.

**Tags:** mining-theory, terminology, block-header, nonce

> **Comments:**
> **username_1**: possible duplicate of [What does nonce mean?](https://bitcoin.stackexchange.com/q/10717/5406),  [When a block is “discovered” how is the nonce determined?](https://bitcoin.stackexchange.com/q/1290/5406), related: [What is a block?](https://bitcoin.stackexchange.com/q/35699/5406), [Can someone explain how the Bitcoin Blockchain works?](https://bitcoin.stackexchange.com/a/13347/5406)  

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## 3 answers

### Answer by username_2 on 2017-05-21. Score: 11

[Nonce](https://en.bitcoin.it/wiki/Nonce) is a 32 bit arbitrary random number that is typically used once. In Bitcoin's mining process, the goal is to find a hash below a target number which is calculated based on the difficulty.   
Proof of work in Bitcoin's mining takes an input consists of Merkle Root, timestamp, previous block hash and few other things plus a nonce which is completely random number. If the output results in hash is smaller than the target hash you win the block and the consensus is reached.   
You need to brute force all possible nonce in order to luckily find a hash smaller than the target hash. It could literally be any number between 0 and 2^31

> **Comments:**
> **username_3**: But if the nonce is 32-bit, that is only 4 billion tries maximum, which is about a few minutes with a good nVidia card, right ? or is the speed much lower than that ?  
> **username_3**: I think you forgot to talk about the extra nonce... and that answers my question above.  
> **username_2**: There is no extra nonce. Your right. its a small number relatively but you have to remember the each second the timestamp changes new tx comes which changes the root and others so all accumulated plus nonce become a large set of options for miners.  
> **username_3**: Only a fixed set of tx are accepted when creating the block. And there is a max number of tx for a block. And please browse for extra nonce ;)    https://bitcoin.stackexchange.com/questions/32603/why-didnt-satoshi-make-the-nonce-space-larger  

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### Answer by username_4 on 2023-08-29. Score: 1

Yet another info and info, **NONCE** stands for: **N**umber used **ONCE**

> **Comments:**
> **username_5**: This does not provide an answer to the question. Once you have sufficient [reputation](https://bitcoin.stackexchange.com/help/whats-reputation) you will be able to [comment on any post](https://bitcoin.stackexchange.com/help/privileges/comment); instead, [provide answers that don't require clarification from the asker](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead). - [From Review](/review/late-answers/90141)  
> **username_1**: Note that “number used once” is a decent memory hook to remember how a nonce is used in cryptography but it’s not the source of the word. My understanding is that it derives etymologically from “for the once”. Nonces don’t have to be numbers.  

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### Answer by username_6 on 2023-06-09. Score: -3

Believe me or not, but I believe the answer is that the nonce helps make it difficult for each miner to solve a block. Just as the difficulty readjusts every ten blocks and blocks are mined every ten minutes, based on the nonce and the difficulty? Did I say that right?


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