Hash rate (also called hash power) measures the total computational power being used to mine and process transactions on a Proof of Work blockchain. It is expressed in hashes per second (H/s), with common units being megahash (MH/s), gigahash (GH/s), terahash (TH/s), and exahash (EH/s). A higher hash rate means more miners are competing to validate blocks, which generally indicates greater network security.