Block Height

Definition

Block height is a block's position within a particular blockchain history, counted from the genesis block at height zero. Its immediate successor has height one, and each later block increases the height by one along that branch. Height is useful for describing confirmation depth, scheduled events, and restrictions that depend on the number of blocks rather than clock time. It is not a globally unique block identifier: competing branches can contain different blocks at the same height. A block hash identifies the particular block more precisely. Height also should not be treated as an exact calendar. Bitcoin targets an average block interval, but individual blocks can arrive sooner or later. When a chain reorganization replaces recent blocks, the block associated with a particular height can change even though the numbering system itself stays the same.