Block Size

Block Size refers to the amount of data that can be stored per block in the blocks added to a blockchain network. Typically block size is referenced as bytes. For example the Bitcoin network has a fixed block size of 1MB.

Not all block sizes are denominated in bytes though. Ethereum’s block size varies and targets 15 million gas per block instead of a fixed byte target. In practice Ethereum’s block size is around double Bitcoin’s at 15 transactions per second added per block versus 7.

Given the small transaction volume that can be included per block and associated high transaction costs given the value of this limited space. Layer 2 solutions are being developed to move some transaction activity off of the main chain for popular networks like Bitcoin and Ethereum. Lightning network is an example of a Layer 2 solution for Bitcoin and Polygon is an example for Ethereum.

An advantage of Block Size limits is they discourage attackers from spamming the network with transactions through a Distributed Denial of Service (DDoS) attack. Only a limited number of transactions can be added per block and the costs associated with adding transactions make the attacks uneconomical.

Further Reading Block Size

Understanding the Block Size Debate