Evidence that a transaction is in an accepted block, with depth added by later blocks.
Confirmation meaning
A transaction receives its first confirmation when it is included in a block on the chain a node currently accepts. Each block added after that increases its confirmation count and makes replacing that history progressively more expensive.
How it works in Bitcoin
Confirmation is not a promise from a miner or explorer. Your own node can verify that the containing block and transaction follow the rules. The suitable number of confirmations depends on value, threat model, and the recipient's risk policy.
A simple example
A coffee payment may be accepted with little or no on-chain confirmation in a trusted setting, while a large settlement may wait for several blocks.
Why Confirmation matters
Transaction terms matter whenever bitcoin moves. Understanding them reduces mistakes involving fees, confirmation status, change outputs and irreversible destinations.
What people often get wrong
Six confirmations is a convention, not a magical point where risk becomes zero. Also, an unconfirmed transaction can still be valid; it simply has not yet been committed to an accepted block.
Quick checks before using the term
- Is the transaction only broadcast or already confirmed?
- Which outputs and fee are being created?
- Can wallet policy replace or delay it?
Apply these questions to the concrete example above. A precise answer is more useful than repeating the definition without naming the actor, rule or failure path.
Check the primary reference
This entry is written in plain English, but the technical source is available when you need exact protocol detail.
Bitcoin Developer Guide: Transactions ↗