# 11. Runtime cost analysis

Every transaction on the blockchain incurs a cost. Miners verify and process transactions, charging transaction fees for their work.

While transaction fees are well-known, there are also execution costs that limit the number of transactions in a block. While transaction fees are well-known, there are also execution costs that limit the number of transactions in a block. These costs, along with block size, determine the maximum number of transactions that can fit in a block. Execution costs are also used to reduce resource consumption when calling read-only functions.
