Block Size in Ethereum

The block size is closely related to the gas concept. Blocks in Ethereum don’t have a fixed size in terms of bytes. Instead, the size is given in terms of gas. This reflects the fact that transactions do not only occupy storage space but also cause computational effort.

The target size of a block is 15 million gas. But in times of high demand, this target can be exceeded up until 30 million gas. To avoid a situation where we have only blocks with a size of 30 million gas, the base fee of the gas price increases.

The rationale is that if transactions are more expensive, fewer users will send transactions, and the block size will shrink to its target.