What Is a Block?
A block is a unit of record on a blockchain containing transactions grouped under specific rules and the information required to verify them.
On this page
What is a block?
A block is a record package in a blockchain network where transactions and related information are collected. When the network accepts a new block, the valid transactions within it become part of the shared history. Thinking of a block merely as a “list of transactions” is incomplete; it can also contain a link to the previous block, timestamp data, and other fields the network uses for verification.
In Bitcoin, a miner proposes a block, and full nodes verify that this block complies with the rules. If a transaction is invalid or if the miner has attempted to produce more new BTC than permitted, the number of transactions in the block does not matter. The nodes enforcing the rules will not accept this block.
The difference between a block and a transaction
A transaction is an instruction intended to transfer value from one address to another, for example. A block, on the other hand, brings many transactions together in the same recording step. Sending your transaction to the network does not mean it enters a block immediately. Fees, network congestion, and the validity of the transaction can affect the waiting time.
In Bitcoin, a transaction located in a block added to the valid chain receives its first confirmation. As new blocks follow it, the number of confirmations increases. Exchanges may wait for a certain number of confirmations before reflecting deposited Bitcoin into an available balance. This number varies by platform.
What does block height indicate?
Block height specifies a block’s position in the chain. It allows for tracking the sequence starting from the first block; it is not the same as the date or the number of transactions. Bitcoin’s average block time is approximately ten minutes, but individual blocks do not occur regularly at these intervals. One cannot calculate a transfer time by assuming the next block will arrive exactly ten minutes later. Other blockchains may have different block times and finality methods.