If you’ve ever traded bitcoin on-chain before, then you probably have experienced the cold sweat and tightened sphincter that is waiting for that first confirmation. Moving money on a network with strange text string addresses and waiting for a miner somewhere in the world to secure it into a block is always going to be nerve-wracking. The longer it takes to confirm, the more self-doubt sets in, and thoughts go racing through your mind like:
- Did I do it right?
- Is this the correct address?
- Did I copy and paste the public key correctly?
- Why is it taking so long?
- Is my money gone?
While you sit and fret about your small fortune that could possibly be lost for all eternity, you might not know that there are several reasons why transactions might take their own sweet time to confirm. A delay in the confirmation of your transactions is pretty normal.
While transactions roughly take 10 minutes if the network is chugging along in standard fashion, we have seen cases where the mempool is so stuffed that remaining unconfirmed transactions could take more than 24 hours to see a confirmation. If you’ve just broadcast a bitcoin transaction to the network and you’re sweating bullets, fret not; we’re here to coach you through the possible reasons.
Why do bitcoin transactions remain unconfirmed?
The bitcoin network is the highest-bid network; miners aren’t running their machines out of the goodness of their hearts; they are there to get paid for their service. The incentive for them is to source the highest-paying transactions and couple them into blocks so they can net the highest return per block they add to the chain.
If your transaction has been depending for some time, it’s most likely a monetary reason, but it’s not the only issue that could put your transactions in limbo.
Processing transactions
The first and most apparent could be that your transaction is simply sitting in the mempool waiting to get picked up by a miner. These transactions have been broadcast successfully to the network but remain incomplete. If the network isn’t busy after 10 – 15 minutes, you should see a confirmation. Depending on your wallet, it might not display on the front end until several confirmations have taken place, this could require 1 – 6 confirmations before your funds reflect, but that doesn’t mean your transaction has not been processed.
Low-fee transaction
The most common reason for an unconfirmed transaction is that it is a low-fee transaction, miners simply ignore your transaction in favour of more profitable ones, and you’ll have to wait until a miner runs out of higher bids to fill a block.
As a result, these transactions can remain unconfirmed for a long time. If your transaction isn’t time-sensitive, you can simply wait until it is picked up, or you can use replace by fee to up the transaction fees to get the attention of miners.
The transaction is larger than the block size limit.
Another reason for an unconfirmed transaction can be if the transaction is larger than the block size limit. Transactions that are larger than the block size limit are often not included in blocks by miners because they cannot be included in a block. This usually occurs when your wallet combines a large number of inputs into one transaction. This is not a matter of fees but the size of your transaction.
The block size limit is the maximum amount of data that can be included in a block. Bitcoin transactions may remain unconfirmed if the transaction is larger than the block size limit. You will either need to consolidate your transaction or pick the UTXOs manually and update your transaction.
Congested with other transactions
Another common reason for slow confirmation times is when the network is slammed with transactions all vying to get into the next block. If there is massive congestion on the network, transactions can remain unconfirmed for some time as miners work on the highest fee transactions first as they attempt to clear the backlog.
Insufficient funds
Transactions need to be properly funded to be included in a block. If the transaction doesn’t have enough fees to cover the network fee, it will likely remain unconfirmed.
Older Protocols
Bitcoin might be backwards compatible with previous versions, but that doesn’t mean that older protocols will give you the best performance. There is obviously a reason why network participants prefer to use a certain version of bitcoin. In rare cases, your wallet might be broadcasting using an old protocol leading to transactions remaining unconfirmed.
- Older protocols may not support the new features that have been added to the Bitcoin network, such as Segregated Witness (SegWit).
- Older protocols may not be compatible with the new software required to run a full node.
- Older protocols may not be able to correctly process the new transaction types introduced, such as opening a Lightning channel.
Incomplete Transactions
These transactions are incomplete as something went wrong on the network, and troubleshooting can be done to sort the issues with these transactions.
- Incorrect Wallet Address: When sending a transaction, you must include the receiver’s wallet address and the amount you want to send. If any of these details are incorrect, the transaction will be sent to the wrong address and will not be confirmed.
- Internet failure: A faulty internet connection means the transaction is not broadcasted to the bitcoin network. If the internet is working, check to ensure the firewall is not blocking the Bitcoin application.
- Rejected transactions: Too many rejected transactions on the bitcoin network may lead to a congested network and eventually to a failed transaction.
- Inactive user: Sometimes, it may appear that the transaction is being confirmed by multiple nodes. However, the transaction is unconfirmed as some wallets are not synchronized with the blockchain network.
- Issues with the receiver’s wallet: Sometimes, you can see multiple nodes confirming your transactions, but your transaction still shows up as unconfirmed. This is usually an issue that happens when specific wallets are not synchronised with the blockchain network. An inactive receiver or someone with a restricted wallet may not be able to display all the information on the network immediately.
Fake or compromised bitcoin wallet
In an absolutely horrific worst case, you could have downloaded a fake or compromised bitcoin wallet. While you think you’re signing your keys to perform a transaction, what you see on the user interface could be coming from a database and not from the bitcoin blockchain. The hacker could have moved your funds to a wallet they own which is why your wallet interface is not in consensus with what you see on your node or block explorer.
The node is down
Perhaps you’re running your bitcoin wallet with your own full node, or you’re using a third-party node to broadcast the transaction. If that node is down, there is no way for your wallet to communicate with the bitcoin network and so your transaction may have never hit the mempool, and miners are not aware of it despite you actioning the transaction in your wallet.
Do you take self-custody of your stack?
If you’re new to bitcoin and have not ventured down the self-custody rabbit hole, what is stopping you? If you’re already self-sovereign, how has the experience been since you took hold of your funds? Let us know in the comments down below. We’re always keen to hear from bitcoiners from around the world.
