<p>The extra nonce is just like the normal nonce in a block header. It is "calculated" by using a counter which increments every time all of the possible nonces for the block header nonce field are exhausted. This process of incrementing the nonce and then the extra nonce is repeated until a valid block hash is found.</p>

CC BY-SA 4.0
2018-07-24T08:00:37.897Z
I'm not sure if this still matters since Bitcoind dropped mining, but in the original implementation didn't extra nonce reset to zero when the timestamp changes, but the regular nonce only when it overflows?
Raghav Sood
CC BY-SA 4.0
2018-07-24T08:03:37.853Z
The extra nonce actually never reset in the original implementation and would actually continue counting up over multiple blocks. It would only increment on nonce overflows, but it would be reused across blocks. E.g. if a block had been found with an extra nonce of 2, the next block to be mined would start with an extra nonce of 3 instead of 0.
Ava Chow
CC BY-SA 4.0
2018-07-24T07:36:17.877Z
2018-07-24T07:36:17.877Z
Ava Chow
<p>The Extra nonce for the genesis block in bitcoin core is <code>0x010445</code>, how was this value calculated?</p>

CC BY-SA 4.0
2018-07-24T05:54:13.090Z
An extra nonce is just some random data that's part of the coinbase tx. It isn't really calculated.
Raghav Sood
<bitcoin-core><bitcoin-core-development><nonce>
How is the ExtraNonce calculated in Bitcoin Core
Barney Chambers
# How is the ExtraNonce calculated in Bitcoin Core

(Asked by: username_0 on 2018-07-24)

The Extra nonce for the genesis block in bitcoin core is `0x010445`, how was this value calculated?

**Tags:** bitcoin-core, bitcoin-core-development, nonce

> **Comments:**
> **username_1**: An extra nonce is just some random data that's part of the coinbase tx. It isn't really calculated.  

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## 1 answers

### Answer by username_2 on 2018-07-24. Score: 2

The extra nonce is just like the normal nonce in a block header. It is "calculated" by using a counter which increments every time all of the possible nonces for the block header nonce field are exhausted. This process of incrementing the nonce and then the extra nonce is repeated until a valid block hash is found.

> **Comments:**
> **username_1**: I'm not sure if this still matters since Bitcoind dropped mining, but in the original implementation didn't extra nonce reset to zero when the timestamp changes, but the regular nonce only when it overflows?  
> **username_2**: The extra nonce actually never reset in the original implementation and would actually continue counting up over multiple blocks. It would only increment on nonce overflows, but it would be reused across blocks. E.g. if a block had been found with an extra nonce of 2, the next block to be mined would start with an extra nonce of 3 instead of 0.  

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