Block confirmation speed refers to the rate at which new blocks are added to a blockchain, and how quickly transactions within those blocks are verified. It impacts how long users have to wait before their transactions are considered secure and irreversible.

When a transaction is initiated, it is included in a block by miners or validators. Each time a new block is added on top of that block, the transaction receives a confirmation. The more confirmations a transaction has, the more secure it is deemed to be. Different blockchains have varying confirmation speeds.

For example, Bitcoin typically has a confirmation time of about 10 minutes, while Ethereum can confirm transactions in around 15 seconds. Factors influencing confirmation speed include network congestion, block size, and the mechanism used to validate transactions.

Faster confirmations are often preferred for user experience, particularly in situations that require quick settlements, such as in retail transactions.