What is a Bitcoin confirmation?
Quick Answer
A confirmation means your transaction has been included in a block on the blockchain. Each new block after that adds one more confirmation, making the transaction exponentially harder to reverse.
TL;DR
1 confirmation = in a block. 6 confirmations (~1 hour) = considered final for large amounts.
Key Takeaways
- 1A new block arrives roughly every 10 minutes
- 2Exchanges typically credit deposits after 1–3 confirmations
- 36 confirmations is the traditional standard for finality
- 4Zero-confirmation transactions can still be reversed
Full Explanation
When you send Bitcoin, the transaction first sits in the mempool — a waiting room. A miner then includes it in a block: that's confirmation number one. Every subsequent block mined on top adds another confirmation, burying your transaction deeper in the chain's history.
Why confirmations matter: reversing a transaction would require redoing the work of every block above it, which becomes practically impossible after a few blocks. That's why recipients scale their requirements to the amount — a coffee shop might accept 1 confirmation, while an exchange crediting a large deposit may wait for 3–6.
Practical expectations: blocks arrive roughly every 10 minutes on average, but the gap is random — sometimes 1 minute, sometimes 40. If your transaction is stuck at zero confirmations for hours, the fee you paid was likely too low for current network demand; our fee estimator shows what miners currently expect.