What, either technically or not, is preventing bitcoin core miners from expanding the number of transactions included in each block?

Wouldn't the corresponding increase in maximum number of transactions per second, and higher compensation per block, be a welcome benefit?

  • FYI, I have purposely not mentioned SegWit2X or BitcoinABC to avoid annoying anyone. Dec 19, 2017 at 23:00
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    Well their blocks wouldn't be accepted by the network. Do you mean how could they create a forked currency in which this rule does not apply? Dec 19, 2017 at 23:14
  • Thanks for giving this qiestion some thought, @Pieter. I thought the block size limit is not a "hard limit", i.e. not coded-in, but more or less simply agreed-upon. If I forked the core code to not have that limit but didn't modify any other code, my node could accept bigger blocks, as well as the current concensus-size blocks, no? Is there some place where this discussion would be better suited? I guess I really need to get my head into the code and see. Dec 20, 2017 at 0:09
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    No, it is absolutely a hard rule. If you modify your miner's node to produce a block with a larger size, it will not be a valid Bitcoin block. Miners doing so are effectively doing the same as turning themselves off. Dec 20, 2017 at 0:21

1 Answer 1


The same thing that keeps them from increasing the mining block reward. Everyone else would consider their blocks invalid and so there would be no benefit at all.

  • Thanks for the answer, David. I know you must be extremely busy. I was hoping for a slightly more technical answer, and possibly some detail about the seemingly political problem of block-size, from your perspective. Dec 20, 2017 at 0:11
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    @MaxVernon Well, you asked what's preventing miners. The answer is that there's no consensus of stakeholders that the block size should be increased. I'm not sure we have any good way to know exactly why there's no consensus. Dec 20, 2017 at 0:57

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