Blockchain By Example

Block size

Welcome to the most controversial issue in Bitcoin!

Block size is simply the size, in bytes, of the serialized block. Initially, Bitcoin's block had a maximum size set to 1 MB. This limit was introduced initially by Satoshi to protect the network against DOS attacks, until it was recently raised after the introduction of Segwit. Segwit, or Segregated Witness, is a technique enabling the production of blocks with a size of up to 4 MB by putting their signatures (which use roughly 60 percent of the transaction space) in an extra space, enabling block capacity to be scaled while maintaining backward compatibility. Segwit introduced the concept of weight instead of size, enabling old nodes (which recognize only 1 MB blocks) to see ...