<p>The network does not need to agree on what the next block looks like, until it has been mined. Miners act independently to create new blocks, each miner can (and probably will) include slightly different transactions, in a slightly different order, in the block templates that they are mining on. In fact, a miner could fill a block up entirely with otherwise unbroadcast transactions, that no other node on the network would have knowledge of before that miner published a valid block containing said transactions to the network.</p>
<p>The blockchain record <em>is</em> the method by which the network comes to independently agree on the specific ordering of transactions. Until the time at which a new, valid block is added to the chain tip, nodes on the network will not know what the next block will look like.</p>

CC BY-SA 4.0
2021-06-08T01:40:11.237Z
Does the block have to have a certain number of transactions?
Jiminion
CC BY-SA 4.0
2021-06-08T03:09:26.240Z
@Jiminion each block will contain a coinbase transaction, but after that there is no specified number of transactions required. It could have none, or it could be full (up to the weight limit)
chytrik
CC BY-SA 4.0
2021-06-07T21:24:49.863Z
2021-06-07T21:24:49.863Z
chytrik
<p>Based on my understanding, the blocks are made up a group of transactions.  But somehow, the network needs to both agree on which transactions are part of the block and also (I would think) the order of these transactions.  How is this done?  I assume there are lots of transactions going on and I don't know how all parts of the network know exactly what constitutes the next block.</p>

<transactions><block>
How does the mining network know/agree when a block has been defined and thus needs to be mined? (The hash determined.)
Jiminion
# How does the mining network know/agree when a block has been defined and thus needs to be mined? (The hash determined.)

(Asked by: username_0 on 2021-06-07)

Based on my understanding, the blocks are made up a group of transactions. But somehow, the network needs to both agree on which transactions are part of the block and also (I would think) the order of these transactions. How is this done? I assume there are lots of transactions going on and I don't know how all parts of the network know exactly what constitutes the next block.

**Tags:** transactions, block


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## 1 answers

### Answer by username_1 on 2021-06-07. Score: 3 | Accepted answer

The network does not need to agree on what the next block looks like, until it has been mined. Miners act independently to create new blocks, each miner can (and probably will) include slightly different transactions, in a slightly different order, in the block templates that they are mining on. In fact, a miner could fill a block up entirely with otherwise unbroadcast transactions, that no other node on the network would have knowledge of before that miner published a valid block containing said transactions to the network.

The blockchain record *is* the method by which the network comes to independently agree on the specific ordering of transactions. Until the time at which a new, valid block is added to the chain tip, nodes on the network will not know what the next block will look like.

> **Comments:**
> **username_0**: Does the block have to have a certain number of transactions?  
> **username_1**: @username_0 each block will contain a coinbase transaction, but after that there is no specified number of transactions required. It could have none, or it could be full (up to the weight limit)  

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