What Is a Transaction Confirmation?
A confirmation is a measure of acceptance tracked as a transaction is included in a block, followed by the addition of subsequent new blocks.
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What does transaction confirmation mean?
Transaction confirmation is the measure describing a transfer being recorded into the blockchain history and having new blocks added behind it. In Bitcoin, when a transaction enters a block on the valid chain, it receives one confirmation. When the next block is added, the confirmation count becomes two. A transaction sent to the network but not yet included in a block has zero confirmations.
As the number of confirmations increases, it becomes harder to alter the history containing the transaction. However, this count does not imply the same level of security across all networks. Six confirmations on Bitcoin and six blocks on another network do not mean equal time or equal finality. The network’s block production and finality rules are also important.
Why isn’t exchange balance updated immediately?
Imagine you are depositing Bitcoin to an exchange and the platform is waiting for three confirmations. When the explorer shows the first confirmation, the funds appear on the chain; however, the exchange may not yet add it to your available balance. After the third confirmation, the platform may also have its own processing time. Checking the required number on the deposit screen prevents unnecessarily making a second transfer.
Although the average block time in Bitcoin is approximately ten minutes, three confirmations do not mean exactly thirty minutes. Blocks are sometimes found in quick succession and sometimes with long intervals. The waiting time before being included in the first block is also added to this.
What does a confirmation not guarantee?
A confirmation does not verify that you wrote the recipient address correctly or that the asset you sent is supported by the exchange. A transaction made to the wrong address can also be confirmed. An exchange might not recognize a deposit on the wrong network. Verification must be done before sending: the network, asset, recipient address, and if necessary, memo or tag information must match. Seeing “successful” on an explorer is not a substitute for these checks.