How large can a blockchain block be? This is not specific to the current bitcoin blockchain or any blockchain. Just assuming you are creating a blockchain, how large can the blocks be?

Also what are the pros and cons of large blockchain blocks?

  • A blockchain does not have a theoretical limit. The things that limit blockchain is the hardware we have so for example if bitcoins blockchain is 1000000000000 tb then miners need to get more than that tb which is a problem to the miners. Also one more thing that could limit the blockchain security is what hashing algorithm you use. if u use sha1 the limit is much smaller than sha512. But none of these are a limit to a blockchain just some restrictions to consider.
    – Varun W.
    Commented Feb 12, 2022 at 17:04

1 Answer 1


To my knowledge, there is no theoretical limit to the size of a blockchain block - you can design it to be as large as you would like it to be as long as there is enough storage space on the network's devices.

The advantage of large blocks would be that you can fit more data inside them. In the case of Bitcoin, for instance, you would be able to include a larger amount of transactions into a block, which would decrease the wait times for initial mining as well as fees.

The disadvantage is that every block has to be broadcasted over the network, validated by its peers (full-nodes) and subsequently stored. Large block sizes can lead to a blockchain quickly gaining mass, which reduces the amount of devices that it can be stored on. It may also allow the blockchain to be misused for data storage purposes (e.g., Satoshi's whitepaper stored inside the Bitcoin blockchain), as the fees on transaction sizes would generally be lower.

Ideally the block-size should be chosen large enough for the blockchain to fulfill its purpose (e.g., storing transaction data), but small enough so that it does not pose unnecessary burden on the network's peers.

  • But even in the current bitcoin blockchains more transactions just means more blocks therefore more burden to network's peers.
    – YulePale
    Commented Feb 12, 2022 at 16:07
  • Yes but the more peers the less load the less pears the more load. So if there are 7 billion miners and 5000 transactions per sec then u dont have to worry but if there are 5000 peers and 7 billion transactions per sec than that might be a problem. But bitcoins peers number is mostly in a uptrend so we dont have to worry.
    – Varun W.
    Commented Feb 12, 2022 at 17:08

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