Block Duration
In short: Block duration, often called block time, refers to the time required to generate new blocks in a blockchain-based system.
Block duration, often called block time, refers to the time required to generate new blocks in a blockchain-based system. Most networks aim for a target average, and the actual gap between two blocks varies around it.
Why it matters
Block duration affects how quickly a transaction receives its first confirmation and how long it takes to become final. Shorter block times give faster feedback but can cause more temporary forks, because new blocks have less time to reach every node. In Proof of Work chains, mining difficulty adjusts so that blocks keep arriving near the target even when mining power changes; Bitcoin, for example, aims for about ten minutes per block. Exchanges take block time into account when deciding how many confirmations a deposit needs.
Example
Suppose a network produces a block about every ten minutes on average and an exchange requires three confirmations. A deposit will then typically be credited after roughly half an hour, although a run of slow blocks can make it take longer. On a network with much faster blocks, the same number of confirmations passes in a fraction of that time, which is why deposit waiting times differ from coin to coin on an exchange such as EX5.