<p>The consensus rules (block validity rules) have no notion of an extranonce2; it's the data the miner chooses to insert into the coinbase transaction input's <code>scriptSig</code>.</p>
<p>The requires on that <code>scriptSig</code> are:</p>
<ul>
<li>Between 2 and 100 bytes in length, inclusive.</li>
<li>Since BIP34 it must start with a push of the block height.</li>
</ul>

CC BY-SA 4.0
2024-07-30T23:35:20.110Z
2024-07-31T11:29:18.683Z
2024-07-31T11:29:18.683Z
Pieter Wuille
<p>I am curious about the size constraints for extranonce2. Is its size effectively unlimited, or are there specific limits or practical considerations imposed on it?</p>
<p>Could someone clarify if there are any limitations to the size of extranonce2 or if it can grow indefinitely?</p>

<mining-pools><mining-theory><nonce><stratum>
What are the size constraints for extranonce2?
Mutti Kangungu
# What are the size constraints for extranonce2?

(Asked by: username_0 on 2024-07-30)

I am curious about the size constraints for extranonce2. Is its size effectively unlimited, or are there specific limits or practical considerations imposed on it?

Could someone clarify if there are any limitations to the size of extranonce2 or if it can grow indefinitely?

**Tags:** mining-pools, mining-theory, nonce, stratum


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## 1 answers

### Answer by username_1 on 2024-07-30. Score: 2

The consensus rules (block validity rules) have no notion of an extranonce2; it's the data the miner chooses to insert into the coinbase transaction input's `scriptSig`.

The requires on that `scriptSig` are:

* Between 2 and 100 bytes in length, inclusive.
* Since BIP34 it must start with a push of the block height.


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