What is Transaction Confirmation?

A transaction confirmation is proof that your transaction has been included in a validated block and permanently recorded on the blockchain. More confirmations mean more blocks have been built on top of yours, making reversal increasingly impossible.

How does Transaction Confirmation work?

A signed transaction is broadcast and enters the mempool.
A validator includes it in a block this is 1 confirmation.
Each subsequent block built on top adds another confirmation.
Ethereum reaches finality after roughly 2 blocks (~25 seconds). Bitcoin typically requires 6 confirmations (~60 minutes).

Why does Transaction Confirmation matter?

Unconfirmed transactions can disappear from the mempool or be replaced. Confirmations provide the certainty needed before treating a payment as final.

Key features of Transaction Confirmation

1 confirmation = included in a block
More confirmations = exponentially harder to reverse
Confirmation time varies by blockchain
Exchanges often require 12+ confirmations before crediting deposits

Examples of Transaction Confirmation

A Bitcoin transaction needs 6 confirmations before most exchanges credit it. Ethereum transactions reach finality in about 25 seconds.

Layer 2 transactions on Arbitrum confirm in seconds due to faster block times.