Confirmation
A confirmation indicates that a blockchain transaction has been included in a block and recognised by the network. Additional blocks built afterward can provide further confidence that the transaction will remain part of the accepted blockchain history.
✦ Key Insight
Exchanges and payment services may wait for several confirmations before crediting a deposit. This reduces the risk of accepting a transaction that could still be reorganised or replaced. Different blockchains use different ideas of confirmation and finality.
✕ Common Misconceptions
Assuming one confirmation is always enough
Confusing confirmation with finality
Expecting every blockchain to use the same model
Panicking when an exchange waits longer
Treating a broadcast transaction as confirmed
Detailed Explanation
How It Works
Suppose a Bitcoin transaction is included in block 900,000.
At that point, it has one confirmation.
When block 900,001 is added, the transaction effectively has another block built on top of it.
As more blocks accumulate, reversing the transaction becomes progressively more difficult.
Proof-of-stake systems can have different finality models.
FAQs
How many confirmations are enough?
It depends on the network, transaction value, and service policy.
Can a confirmed transaction ever change?
Rare reorganisations can occur on some networks, which is why additional confirmations matter.
In Practice
Dig Deeper
Transaction Hash
A transaction hash is a unique identifier assigned to a blockchain transaction. It acts like a digital receipt number that lets users track and verify a transfer on the blockchain.
Block Explorer
A block explorer is a tool or website that lets users search and view blockchain data, including wallet addresses, transactions, token contracts, blocks, and network activity.
Blockchain
A blockchain is a decentralized digital ledger that records transactions in blocks, links those blocks together, and makes the record difficult to alter.