Block height is the count of how many blocks have been confirmed on a blockchain up to a particular block. Starting from the genesis block (often called block 0), each new block increases the chain’s height by one, making block height a simple way to describe a block’s position and the network’s progress.
How block height works
You can think of block height like the step number on a staircase. A block at height 1 comes right after the genesis block, a block at height 2 comes after that, and so on. Because each block references the previous block’s hash, the height also implicitly reflects the ordering of blocks in the chain.
Most blockchain explorers show block height prominently. When someone says, “This transaction is in block 840,000,” they are pointing to the block height as a precise location. In proof of work networks like Bitcoin, height rises as miners produce new blocks. In proof of stake networks, validators propose and finalize blocks, and height increases as blocks are added.
Why block height matters in practice
Block height is widely used for confirmations, indexing, and software rules. For example, exchanges often wait for a certain number of additional blocks after the block containing your transaction before crediting a deposit. That “number of confirmations” is based on block height differences.
Developers also use block height to trigger protocol upgrades or enforce new rules at a known point in the chain, since every node can independently verify the height. During temporary chain splits, competing branches can exist at similar heights, and nodes typically converge on the canonical chain based on the consensus rules.