A confirmation is the step by which a transaction is validated and added to the blockchain. The process starts from the moment you initiate a transaction and continues until the transaction is included in a block, and that block is “cemented” by adding additional blocks, each representing a confirmation.
In short, confirmations are your guarantee that your transaction is valid, secure and irreversible.
Stages of a confirmation
- Initiating the transaction
You send funds from your wallet to another user. For example, you make a payment in Bitcoin to a friend.
- Network broadcasting
The transaction is broadcast on the blockchain network and ends up in the mempool (a virtual space where transactions wait to be processed).
- Processing by miners or validators
Miners (in the case of Proof of Work) or validators (in the case of Proof of Stake) select transactions from the mempool and organize them in a block.
- Adding the block to the blockchain
Once the block is validated (through the mining or staking process), it is added to the blockchain and the transaction receives its first confirmation.
- Additional confirmations
Each new block added after the block containing the transaction is an additional confirmation.
Example: For Bitcoin, a transaction is considered completely secure after 6 confirmations, which means that 6 blocks have been added after the initial block.
Why are confirmations important?
Confirmations are the foundation that underpins the security and functioning of blockchain networks. Here are some reasons why they are essential:
1. Increased security
The more acknowledgments the transaction has, the more difficult it is to attack or modify. Adding new blocks strengthens the transaction in the blockchain structure, ensuring its permanence.
2. Transaction finality
Exchanges, merchants and other blockchain services require a certain number of confirmations to avoid risk and ensure that the transaction is irreversible. For example:
- Bitcoin: 6 confirmations are standard for large transactions.
- Ethereum: A transaction is often considered safe after 12 confirmations.
- Litecoin: May require 2-6 confirmations, depending on the platform.
3. Prevent double spending
The problem of “double-spending” involves the possibility of a user trying to use the same Bitcoin in two separate transactions. Confirmations make this impossible because each validated transaction is publicly recorded and cannot be reused.
How does the specific cryptocurrency influence the confirmation process?
The number of confirmations required depends on the cryptocurrency and the network protocol. Some networks are designed to provide quick confirmation (e.g. Proof of Stake based networks ), while others (such as Bitcoin) prioritize security, requiring more confirmations.
For example:
- Bitcoin: The interval between blocks is about 10 minutes, which means 6 confirmations can take about 60 minutes.
- Ethereum: Blocks are produced every 15 seconds, so a similar number of confirmations can be obtained much faster.
Practical examples of confirmation
Let’s analyze how confirmations work in a real scenario:
- Online merchant:
When making a purchase of products with Bitcoin, the store will not consider the transaction complete until at least 3 confirmations for small payments and 6 confirmations for large payments are made.
- Transfers between wallets:
When you transfer Ethereum to a friend, wallet apps can display notifications like “1 in 12 confirmations completed,” so you know the status of the transaction.
What happens if a transaction is not confirmed?
Unconfirmed transactions remain in mempool until they are picked up by miners/validators and included in a block. Some may expire and be returned to the wallet. This often happens because of a low transaction fee that discourages miners.
Confirmations in the blockchain give users:
- Security: Each confirmation increases the level of confidence that the transaction will remain permanent.
- Transparency: Blockchain provides public records of all transactions.
- Trust: Once included in a valid blockchain, the transaction becomes unchangeable.
You can check the status and number of confirmations of any transaction on our dedicated blockchain transaction verification page.