Block Height

Block height is the number of blocks that come before a given block in a blockchain, counted from the genesis block at height zero. Because blocks are added in one ordered chain, height acts as the network's clock and its confirmation counter: a transaction buried under more blocks becomes progressively harder to reverse, which is why exchanges wait for a set number of confirmations before crediting a deposit. Block explorers display the current height of the chain, and protocol events such as Bitcoin's halving are scheduled at specific heights rather than calendar dates. If two nodes briefly report different blocks at the same height, the network has a temporary fork that consensus resolves within a few blocks.