What is Confirmation?
Crypto Glossary Definition
A transaction is considered to be confirmed once it has been written to the blockchain. If a transaction has multiple confirmations, it means that additional blocks have been mined after the block that contains the transaction in question. The higher the confirmation number, the more certainty that a coin has not been double spent.
Why Confirmation Matters
A confirmation is each additional block mined on top of the one containing your transaction — more confirmations mean it's progressively harder for that transaction to be reversed, which is why exchanges typically wait for several confirmations before crediting a large deposit.
Confirmation in Practice
A freelancer based overseas receives payment for a project in Bitcoin and watches the transaction appear in their wallet almost immediately after the client sends it, but the funds are still marked as unconfirmed on the block explorer. A few minutes later, the transaction gets included in a new block, earning its first confirmation, though the freelancer's exchange still shows the deposit as pending. This is standard practice: most exchanges wait for multiple confirmations, often around six for Bitcoin, before actually crediting a deposit to a user's tradable balance, because each additional block mined on top of the one containing the transaction makes it exponentially more difficult and expensive for anyone to reverse it through something like a 51% attack. For a very small transaction, a merchant might accept payment after zero or just one confirmation, judging the tiny fraud risk not worth the wait. But for a large transaction, that same merchant would wait for far more confirmations before releasing goods or services, since the cost of successfully reversing a heavily confirmed transaction becomes prohibitively expensive for an attacker. The freelancer checks back an hour later, sees the deposit has cleared with well over a dozen confirmations, and finally has full, spendable access to the funds on the exchange.
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