What Are Confirmations in Cryptocurrency?
In cryptocurrency, confirmations are a measure of how many blocks have passed since a transaction was added to a coin’s blockchain. The more confirmations, the more secure the transaction.
How Many Confirmations Should I Wait For?
For small transactions buyers and sellers may agree to wait for zero transactions, for larger transactions parties may want to wait for more blocks.
For Bitcoin specifically, as a very general rule of thumb, 3 blocks is a good safe middle ground, 6 confirmations is advised for large transactions, and for very large transactions one may wait for as many as 60 confirmations.
TIP: Each merchant/exchange/etc must decide how many confirmations they require for each coin. There is no magic number and the number of confirmations needed too be 100% safe increases over time. That said, there are general accepted best practices. For example for Bitcoin: 0 to 1 confirmations for small payments, 3 in general for general safety, and 6 for bigger transactions, 60 for very large transactions. However, but there is no actual requirement.
How Long Do Confirmations Take?
How long confirmations take depends on the coin, as each coin has a different timeframe for how quickly blocks are mined.
With Bitcoin a block is added roughly every 10 minutes. That means there will be 1 confirmation every 10 minutes starting once an unconfirmed transaction is added to the blockchain (an unconfirmed transaction is a transaction that is waiting to be added to the blockchain by miners). Then, each block added after that initial block results in 1 confirmation. So, 1 confirmation takes 10 minutes, 3 takes a half hour, etc.
Each Crypto Has Different Confirmation Rates and Requirements
Each crypto has its own rate at which blocks are mined, so for example with Ethereum where blocks are mined much faster, you would be waiting for way more confirmations! However, that detail aside, the general concept is the same for all blockchain-based coins.
Why Wait For Confirmations
Every block that goes by adds an extra layer of security, because it shows the network has accepted that block as valid via consensus and that nothing went wrong (for example, there was no double-spend attack), and thus it decreases the chances of a transaction being reversed.
How to Track Confirmations
You can see how many confirmations any transaction has by looking at the coin’s blockchain. You can run a full node to see this information for yourself, but a simple way to see this information is to check out a coin’s “block explorer.”
For Bitcoin and Ethereum you can explore blocks via blockchain.com and etherscan.io. To see confirmations there simply click on or search for any valid transaction number (any Tx Hash) on those sites.
TIP: If you sent crypto to a wallet for any reason, for a payment, to transfer to an exchange, etc and you don’t see the funds, try checking the blockchain. 9 times out of 10 your transaction is sitting around unconfirmed or the exchange/merchant/etc is still waiting for additional confirmations. Sometimes, when a chain is congested, this whole process can be very slow. If all else fails, you can always open up a ticket with an exchange/merchant and give them your TX number.