One-sentence answer
A transaction gets its first confirmation when it enters a valid ; each later valid on that chain adds another confirmation.AT A GLANCE · EXPAND A STEP
01Broadcast: 0 confirmations
Visible but not yet in a block.
02Included: 1 confirmation
In a block on the current valid chain.
03More blocks follow
More work reinforces history, without absolute irreversibility.
This diagram explains relationships, not the complete protocol implementation.
Broadcast is not confirmation
After a wallet sends a transaction, it propagates through the peer-to-peer network and may enter many ’ mempools. Other people can see it before it is in a .
still check signatures and available funds. Wide propagation does not make an invalid transaction valid.
Accumulation starts inside a block
A miner includes the transaction in a valid . Once accept it, the transaction is usually described as having one confirmation. Every valid built afterward increases the work needed to rewrite that history.
A confirmation is not a certificate from a central institution. It is depth within a chain of accumulated work.
How many confirmations are enough?
There is no single number for every payment. Small payments, reversible services, and high-value irreversible delivery have different risks. Recipients choose policies based on amount, counterparty, other protections, and waiting cost.
BTCVisual does not provide transaction advice; this page explains the mechanism itself.
TRY IT YOURSELF
Why is a changed record detectable?
…Current hash…Matches original history
…Current hash…Matches original history
…Current hash…Matches original history
Editing data invalidates its original fingerprint. Recomputing it changes later references too. Real Bitcoin also uses proof of work to make rewriting history costly.
Teaching limits: one SHA-256 over teaching text, not Bitcoin’s full block format or double hashing. Difficulty and speed do not represent real mining.
Open standalone experimentCHECK YOUR UNDERSTANDING
Do more confirmations mean more people clicked approve?
A correct answer saves local progress. No account needed.View my learning pathThree things to remember
- ✓A propagated transaction has not necessarily entered a block.
- ✓Confirmations measure depth in a valid chain.
- ✓A waiting threshold is contextual, not one protocol-mandated number for everyone.
A common follow-up
Do more confirmations make a transaction absolutely irreversible?
More confirmations rapidly increase the cost of a reorganization, but “absolute” is not technically precise. Risk depends on accumulated work, network conditions, and context.
Primary sources
Primary sources
These links lead to protocol material, developer documentation, or open-source code—not trading services.