A confirmation is a measure of how firmly a cryptocurrency transaction has been accepted by a blockchain network. A transaction typically becomes “confirmed” once it is included in a block. After that, every additional block built on top of the block containing your transaction counts as another confirmation.
How confirmations work on a blockchain
When you send crypto, your transaction is broadcast to the network and usually sits in a mempool, a waiting area for transactions not yet added to a block. Miners or validators select transactions to include in the next block, verify that they follow the network’s rules (such as valid signatures and sufficient balance), and propose or produce the block. Once the network accepts that block, the transaction has one confirmation.
As more blocks are added, your transaction becomes deeper in the chain. Because each block references the previous one using cryptographic links, changing an earlier block would require rebuilding that block and every block after it, and convincing the network to accept the altered history. Each extra confirmation therefore increases confidence that the transaction is final.
Why the number of confirmations matters in practice
Different services require different confirmation counts based on risk tolerance. A wallet might show a “confirmation” notification as soon as the transaction is included in a block, while an exchange may wait for several confirmations before crediting a deposit. This helps protect against rare reorgs, where competing versions of the chain briefly exist, or against double-spend attempts in some proof-of-work contexts.
Confirmations matter because they translate blockchain consensus into practical settlement, helping users and businesses decide when a payment is safe to treat as irreversible.