Guides / How confirmations work
How confirmations work
A confirmation is a block mined on top of your transaction. The more there are, the harder it becomes to undo, which is why "wait for confirmations" is the golden rule of getting paid.
On this page
What a confirmation is
When your transaction is included in a block, it has one confirmation. Every block mined after that sits on top of yours and adds another confirmation. So "confirmations" is really just how deep your transaction is buried in the chain.
Why more is safer
To reverse a confirmed transaction, an attacker would have to re-mine its block and every block after it, faster than the rest of the network builds the real chain. Each extra confirmation makes that exponentially more expensive. A brief re-ordering of recent blocks (a reorg) can happen naturally at shallow depth, which is exactly why you wait.
Zero-conf risk
An unconfirmed (zero-confirmation) transaction is just a proposal sitting in the mempool. It can still be replaced or dropped, so don't treat it as final. Wait for it to make it into a block.
How many to wait for
| Coin | Block time | Common rule of thumb |
|---|---|---|
| Bitcoin | ~10 min | ~6 confirmations |
| Litecoin | ~2.5 min | Similar depth, but far less waiting because blocks are faster |
| Monero | ~2 min | ~10 blocks (this is the protocol's output-unlock window, so you cannot spend sooner) |
These are conventions, not hard rules, and bigger amounts deserve more patience.
On testnet
Testnet block timing is erratic, especially on Bitcoin testnet3: confirmations may arrive in a burst or stall for a while. That's normal and part of what testnet teaches. Watch it happen live on TestnetScan. If a transaction seems stuck, see debugging a stuck transaction.
Testnet coins are fake money
- They have no market value, so never buy or sell them.
- Never use a real seed phrase or import a real wallet on testnet.
- Never send mainnet BTC, LTC, or XMR to a testnet address.