A blockchain is made up of a series of connected blocks. A block is simply a file containing a group of recently executed network transactions staged to be added (or chained) to the previous block on the blockchain at a given interval of time. Block height refers to the total number of blocks connected in the blockchain prior to the newly added block.
Importance of Block Height
The block height number is an important measure of the approximate rate at which new blocks are being added to a blockchain and an indication of its current size and creation rate of the network. Block height number can be used as an identifier to reference the location of a particular block that has been completed in the past on the network using a block explorer.
The first block in a blockchain is called the genesis block, considered to block zero ( i.e. having a block height of zero). As the network grows and users begin to transact on the network, blocks are mined by solving complex mathematical puzzles requiring extremely high levels of computational power for a block reward of 6.25 BTC in the case of Bitcoin. This mining activity to confirm Bitcoin transactions continually increases the block height of the entire network, consequently bolstering its credibility and security.
Block generation varies from blockchain to blockchain determined by the block time, i.e. the time it takes to generate a new block. The impact of the block time on a network is evidently seen in the comparison between the block heights of the Bitcoin and Ethereum networks. Although it is the first-ever cryptocurrency, the current Bitcoin block height is about 700,000+; a far cry from the Ethereum block height, which is about 13,000,000+. This is simply attributed to the estimated block time of Bitcoin, which is currently mined over 10-min intervals in contrast to about 10 – 20 seconds intervals on the Ethereum blockchain.