Guide
What Is a Bitcoin Confirmation? How Many Do You Need?
The bottom line: a confirmation is a block stacked on top of your transaction — the more, the harder it is to reverse
A Bitcoin confirmation is the count of how many new blocks have been stacked on top of the block that contains your transaction. The moment your transaction is first included in a block, that's "1 confirmation." Add one more block on top and it becomes "2 confirmations." The higher the confirmation count, the harder it becomes to reverse (roll back) that transaction.
Key points of this article
- Confirmations = the number of blocks stacked on top of your transaction's block
- A new block is produced on average about every 10 minutes (though it varies)
- The more confirmations, the harder tampering or rollbacks become — and the safer the transaction
- Exchanges often require roughly 1 to 6 confirmations before crediting a deposit
How confirmations are counted
| Status | Meaning |
|---|---|
| 0 confirmations (unconfirmed) | Sitting in the mempool, not yet included in a block |
| 1 confirmation | The transaction has been included in a block |
| 6 confirmations | Five more blocks have been stacked on top of it |
Since a block is produced on average about every 10 minutes, 6 confirmations take roughly an hour as a rule of thumb. But that's only an average — in practice several blocks can arrive within minutes, or a single one can take 30 to 40 minutes. For the bigger picture of how it all works, see How Bitcoin Works.
Why more confirmations mean more safety
Bitcoin's transaction history is a chain in which each block links to the one before it. To rewrite an old transaction, you would have to redo every block stacked after it — a task that becomes practically impossible as confirmations pile up. The mining mechanism behind this is explained in What Is Mining?.
How long should you wait?
- Small payments: 1 confirmation is often plenty for everyday use
- Deposits to an exchange: it varies by service, but requiring roughly 1 to 6 confirmations is common
- Large or important transactions: waiting for 6 confirmations is generally considered safer
If a confirmation feels slow, the cause is usually an insufficient fee or network congestion. Check What to Do When a Bitcoin Transaction Won't Confirm and What Is the Mempool?.
The risk of 0 confirmations (0-conf)
A 0-confirmation transaction — one that hasn't yet entered a block — is not yet final. In theory, it can still be replaced by another transaction carrying a higher fee (a double spend). For anything important, the safe approach is to wait for at least 1 confirmation — and several for high-value transactions — before treating a payment as "received."
Frequently asked questions
How many confirmations should I wait for on Bitcoin?
It depends on the purpose. For small amounts, 1 confirmation is often enough in practice; deposits to an exchange typically need roughly 1 to 6 confirmations; and for large or important transactions, waiting for 6 confirmations is generally considered safer.
How long does 1 confirmation take?
Since a block is produced on average about every 10 minutes, the rough estimate is about 10 minutes. However, the actual interval varies, and if the network is congested and your fee is low, the first confirmation can take several hours.
Is it safe to accept a 0-confirmation transaction?
A 0-confirmation transaction is not yet final, and in theory it can still be reversed by a double spend. For important payments, it's safer to wait for at least 1 confirmation — and ideally several — before treating it as complete.
Sources & references
A note before you invest
This article is for informational purposes only and is not investment advice. Bitcoin carries risks including price volatility, hacking, and loss of funds. Make investment decisions at your own responsibility and only with money you can afford to lose. Tax rules and regulations can change, so always confirm the latest details from official primary sources.
Sources
FAQ
- How many confirmations should I wait for on Bitcoin?
- It depends on the purpose. For small amounts, 1 confirmation is often enough in practice; deposits to an exchange typically need roughly 1 to 6 confirmations; and for large or important transactions, waiting for 6 confirmations is generally considered safer.
- How long does 1 confirmation take?
- Since a block is produced on average about every 10 minutes, the rough estimate is about 10 minutes. However, the actual interval varies, and if the network is congested and your fee is low, the first confirmation can take several hours.
- Is it safe to accept a 0-confirmation transaction?
- A 0-confirmation transaction is not yet final, and in theory it can still be reversed by a double spend. For important payments, it's safer to wait for at least 1 confirmation — and ideally several — before treating it as complete.
This article is informational only and is not financial, investment, or trading advice. Prices are reference snapshots and may be outdated. Always do your own research.
