Roughly every ten minutes, a new block is created and added to the blockchain through the mining process. This block verifies and records any new transactions. The transactions are then said to have been confirmed by the Bitcoin network.
For example, if Sean sends one bitcoin to John, this transaction will remain “unconfirmed” until the next block is created. Once that block is created and the new transaction is verified and included in that block, the transaction will have one confirmation. Approximately every ten minutes thereafter, a new block is created and the transaction is reconfirmed by the Bitcoin network. While some services are instant or only require one confirmation, many Bitcoin companies will require more as each confirmation greatly decreases the likelihood of a payment being reversed. It is common for six confirmations to be required which takes about an hour.
Once you make a transaction, your wallet should give you an option to view the transaction on a block explorer or give you the transaction ID.
A transaction ID looks like this: 7a43510802e113b7059851ef0a8a5c3625db37541861dd982f56253b2d5c4ff9
To check the number of confirmations for a transaction, paste the ID into a block explorer like blockchain.info:
Press enter and then you’ll see more details about your transaction:
There is a greater than 60% chance your transaction will be confirmed within 10 minutes if you pay a high enough fee:
If your transaction is unconfirmed for hours, just wait. If more than 72 hours pass and your transaction still isn’t confirmed, you can re-send the transaction.
We recommend using Electrum wallet, since it allows you to raise the fee on transactions if they get stuck.
Coinbase requires three confirmations before a transaction will show up and be spendable in your Coinbase account.