What is Epoch?

While this varies depending on the blockchain protocol, an epoch generally refers to a specific number of blocks — or a specific or approximate period of time. Generally found on blockchains that utilize Proof of Stake (PoS), different PoS protocols have different ways of defining an epoch (if they use them). Epochs are used to reach security checkpoints, distribute staking rewards, or assign a new group of blockchain validators. For example, an Ethereum epoch lasts 30,000 blocks — while a Cardano epoch lasts five days.