What does an unconfirmed Bitcoin transaction mean? Unconfirmed Bitcoin transaction: what to do

The Bitcoin network is growing, the exchange rate is rising, and more and more often Bitcoin users are faced with a problem when a Bitcoin transaction freezes. Those. Bitcoins seem to have been sent, but they reach the recipient in a few days at best. And most often it happens that the transaction “walks” through the network and returns to the wallet. By the way, this is also one of the positive options for the development of events.

As I already noted, the increase in the number of transactions in the Bitcoin network has led to the fact that many transactions “hang” unconfirmed for several days. Moreover, even an increased commission will not guarantee that your transaction will be processed within the stated few hours. The number of unconfirmed transactions on the network can reach up to 200,000.

The main reasons for this situation are considered to be: an attack on the Bitcoin network and a low transaction fee, and then the manners simply do not process it.

Before sending a payment, I advise you to look at the network load. This can be done also. There you can also see the recommended price per byte.

But you wouldn’t have come to this article if you hadn’t asked the question that I made the title. So, what to do if the transaction is stuck? There is a special service for “pushing stuck” transactions.

To do this, you need to get the HASH of your transaction (below is an example of how to do this on the blockchain):

I deliberately did not rewrite, but copied information from the forum. Everything is described there in a fairly accessible form. If you have any questions, ask them in the comments, we’ll sort it out.

Unconfirmed Bitcoin transactions are becoming more common. This is due to many factors, including the increase in people wanting to make money on cryptocurrency. What ways to correct the situation are there?

Blockchain transactions.

In order to understand what unconfirmed blockchain transactions are, you should understand the nuances of carrying them out to the addressee. If we go from the opposite meaning of this term, then confirmation of a transaction is its merger with the found block. This confirmation is required to prevent double spending. That is, an unconfirmed transaction is one that is in the verification and transition stage.

In the case when a user performs any transaction with cryptocurrency, it must be checked for authenticity and then confirmed. The check takes place on all possible nodes; this is a rather complex process. A transaction is considered confirmed only if there are 6 blocks or more.

After verification has been completed, the transaction is queued in the so-called Memory Pool, a specially designated area for waiting for confirmation of operations.

Blockchain operation scheme.

Since each node has different RAM, the algorithm for checking and performing operations will also be different. If the volume random access memory The mempool is close to the node’s OP volume, the latter sets the minimum commission size. Those transactions whose commission was less are excluded from the node; subsequent transactions are processed only if a commission exceeds the established threshold. When the speed of mining new blocks exceeds the parameters for adding the next transaction to the mempool, the entire operation of the system slows down sharply.

On average, it takes from 15 to 60 minutes to complete a transaction, sometimes more. However, if there are some problems, the wait can last for several days or even more, since the transaction literally freezes.

If after 72 hours (sometimes more or less) the transaction is not included in the block by default, the bitcoins are returned to the sender's wallet.

The number of unconfirmed transactions and mempool size can be viewed on blockchain.info.

Mempool size, number of unconfirmed transactions.

That is, based on these data, we can assume that the transaction confirmation queue will be 90 blocks.

On the blockchain.info website you can find out the average transaction confirmation time on the graph.

Website blockchain.info.

At the end of 2017, due to a sharp increase in BTC price, the number of transactions also increased sharply, and there were up to 20 thousand unconfirmed Bitcoin transactions.

What are the causes of freezing?

The processing period for transactions may take longer for several reasons. Factors predisposing to inhibition of translations are the following:

1. System load. This happens due to sharp jumps in the value of Bitcoin, which in itself is another reason for transaction congestion, or due to the large, critical size of the mempool. According to some data, the workload over the past 2-3 years has increased more than 8 times.
2. Small commission. However, some users deliberately set low transaction fees because they are transferring small amounts and are willing to wait.
3. Amount priority. Larger transaction sizes are transferred first.

That is, in some cases it is difficult for an individual user, the sender of a transfer, to influence the subsequent situation.

How to fix the situation?

Cryptocurrency transaction.

Experts offer several effective ways correcting the situation when a cryptocurrency transaction is not confirmed.

There is almost always an option to simply cancel an unconfirmed transaction:

1. In your wallet, go to the debug console. If the wallet is encrypted, access to it is required. Get it using a combination of walletpassphrase commands – dumpprivkey<адрес транзакции>. If transactions are multipart, you should obtain all access keys and export them.
2. The key(s) must be copied.
3. Delete wallet. You can rename the file or move it so you don't have to download it again.
4. Next, you need to restart the client, which will subsequently create the wallet.
5. Enter the private key using the command combination importprivkey -<ключ>.
6. The new wallet does not contain sent transactions, the funds have been returned to the balance.

Now you can re-create transactions by adjusting them.

Selective commission replacement

Opt-In RBF.

The function is to resend the transaction, but with a higher commission. Normally, a new transfer with increased fees would be considered a double spend by the network, but thanks to Opt-In RBF, nodes are notified of the upcoming new transaction.

Not all miners support this feature, but most do. However, due to the need for additional verification, the transfer will take slightly longer than a regular transaction with a high commission.

Wallets that support selective commission replacement:

• Bitcoin Core;
• Armory;
• Electrum;
• GreenAddress.

Only GreenAdress uses the necessary settings by default; in other wallets you need to set certain parameters.

Double spending

Double spend (doublespend) – repeating a transfer with the same parameters. To achieve this, you must first ensure that the transaction is truly unconfirmed.

This can be done on the website blockchain.info or other similar services.

Blockchain.info.

If after a search the information “unconfirmed transaction” appears, then the operation is waiting for confirmation.

1. Close the wallet and start it again via the command line. If you used Bitcoin Core, set the zapwallettxes parameter. In some cases, you will need to rename or move the mempool.dat file.
2. Create a new transaction, the commission of which will be higher than the previous one.
3. To ensure that the old transaction is not confirmed later, because it is still in the system, you need to set the same input size for the new transfer as it was in the old one. Plus, you need to select additional inputs so that in total it covers the amount of the old transaction with a commission with a margin.
4. Complete sending.

Using CPFP

CPFP.

Such the method will work for the recipient of the transaction, for the sender it is available only if the transaction was completed with change. This is possible in situations where miners, instead of one transaction with a large commission, take a group of transfers, which in total will have higher commissions.

Child Pays for Parents (CPFP) is a method whose essence is to spend one output of an unconfirmed transaction and set a commission that would be enough to include two of them in a block.

You need to do this:

1. In the wallet settings, go to the “Wallet” tab, check the boxes next to “Enable input management”, “Spend unconfirmed change”.
2. Create a new transfer, the input of which is the output of the unconfirmed one. You can specify "change".
3. Calculate the correct commission size, taking into account two transactions.

Thus, two transactions will be available for processing at once, and they will be checked jointly. Miners will receive the maximum commission, the user will receive the inclusion of the transfer in the block.

Dynamic commission change

Dynamic commission change is a wallet option that automatic mode will save the sender from hanging the transaction.

That is, the wallet independently, depending on the network congestion, determines the commission fee allowed for a successful transaction.

In the event that the user initially set a commission less than the required one by this moment, the smart wallet will notify him about this and offer to increase the amount.

For example, the following wallets support the function:

• Bitcoin Core;
• Ledger;
• Electrum; Airbitz;
• GreenAddress.

Wallets can either lower or increase fees. If, even if the wallet parameters are correctly set, the transaction is delayed, you should update the existing wallet.

Acceleration of transactions

Аntpool.com.

Some enterprising companies created so-called “transaction accelerators”, where the sender simply specified a hash, and the miners in the pool processed it. The most common ones are antpool.com, viabtc.com. However, according to some reports, only viabtc.com currently provides this function.

Using ViaBTC, you need to enter the ID of the transaction that is stuck and the captcha in the appropriate windows. The system will recognize the influence of the accelerator and will put the transaction in the decrypted block mined by the pool.

The following ways to increase transaction speed are also provided:

1. Increased commission. An excess of 0.0002 BTC is acceptable.
2. Translation of large volumes. It will be much more effective to transfer a one-time, but large amount, than several small transactions.
3. Using specialized platforms, for example, coinbase.com, where the private keys of both sellers and buyers are stored, and the transfer is carried out within the platform. The blockchain system is not involved.
4. Using wallets with multi-signature functionality. A multi-signature, for example, from GreenAddress, will be confirmation of a reliable translation. The system will take such a transaction into a block much faster.

Some experts advise using open transactions, since such transfers are easier and faster to verify. However, you can forget about the anonymity of the transfer.

How to protect yourself from freezing?

Service.

In order to prevent freezing, you should always follow a few simple rules.

Required:

1. Set the correct commission. If waiting is not possible, you should not save. The approximate cost of the commission relative to the size of the transfer can be found on services like blockchain.info.
2. Use wallets with dynamic changes in commission, listen to their warnings about the advisability of increasing commissions.
3. Enable the option of selective commission replacement. The multi-signature feature wouldn't hurt either. If your wallet does not currently support the options presented, you should consider replacing or updating it.
4. Use resources that have an autonomous transaction system.

By doing these simple rules, you can significantly reduce the waiting time for transaction confirmation to a minimum.

Often when transferring bitcoins, users are faced with non-confirmation of blockchain transactions, this happens due to low commission setting for translation or simply due to network congestion. Miners primarily process transactions with high fees.

Sometimes you have to wait 2-3 days for confirmation. So what to do in this situation? I advise you to use the bitcoin Transaction Accelerator, which belongs to a large mining pool. As a rule, after acceleration, the transaction is confirmed within 20 minutes. There is also Antpool, which works similarly, but to speed up the transaction you will first have to register.

Important: there is a limitation; you can only speed up 100 transactions per day. If it doesn't work, try again later.

Acceleration of blockchain transactions:

1. Go to the blockchain wallet, find your transaction and click “Verify on blockchain.info”
2. Copy the transaction number
3. We go to the transaction acceleration service, insert the transaction number, fill out the captcha and click on “submit”. If the acceleration was successful, a message will appear.
4. We wait 20 minutes and rejoice))) Checked personally!

Still have Antpool there is a telegram bot ( @FastTXbot) https://t.me/FastTXbot, you need to add the bot to your contacts and write the transaction number. When the transaction is confirmed, the bot will automatically notify you. Typically confirmation occurs with the next block or several blocks later.

If everything worked out for you and your transaction was successfully confirmed, please thank me with comments on this article or a couple of satoshis to this address 1NXSuj2kQXZ7QMJf5uH5QroertEpZPRbid

Subscribe to our news channel

Constantly increasing, which means that the blocks in which they are stored fill up faster. After all, the block size remains the same - 1 megabyte. This causes a common problem - transaction delays due to the fact that it is not confirmed (at least 2 confirmations are required).

The waiting time for a transfer can last for several hours and sometimes days. This creates obvious inconveniences, especially in situations where it is necessary to transfer funds within a short time frame. In this material, we will take a closer look at the concept of an unconfirmed transaction and find out what needs to be done in such a situation.

What does an unconfirmed Bitcoin transaction mean?

An unconfirmed transaction is a transaction that, after it was initiated, was not added to the block. The Bitcoin network is supported by miners, who “process” the transfers. They have their own priority - the higher the fee per byte of a transaction, the faster it will be added to new block. So the phenomenon of an unconfirmed transaction is most often a consequence of the low commission that the sender chose.

You can always find out the status of your transfer by simply entering your TXID (your transaction id) into the search field of the blockchain.info website. It displays the number of confirmations and the path of the transaction itself. The number 2 around and the blue status of the “button” with the inscription Confirmations in Blockchain means that the transaction was completed. And if it was not confirmed, then you will see the characteristic inscription Unconfirmed Transaction on a red background.

Provided an adequate commission is set, confirmation takes up to 30 minutes, in otherwise, you can expect 72 hours or even more.

If you are sure that your transaction is stuck and not awaiting confirmation, read this.

Why is the transaction not confirmed?

The main reason for an unconfirmed transaction is the low commission set by the user. Most wallets have the concept of a recommended commission, which the program chooses itself. However, this figure may be either underestimated or overestimated.

It is important to remember that the size of the commission does not depend on the transaction amount. That is, a transaction of 100 bitcoins may be cheaper than 0.01 BTC. It all depends on its size in bytes. In turn, the size depends on the number of related transactions. For example, if you received 1 bitcoin from Dima, Sasha, Katya, and then send these 3 bitcoins to Vakhtang, then 4 addresses (including yours) will participate in this transaction. And that's an extra 600 bytes or so.

But if you dig deeper, it turns out that the long transaction confirmation time is a consequence of the small Bitcoin block size. The network, in conditions of constant growth in the number of participants and transfers, is not able to quickly process them at this stage.

You can even make an approximate calculation. The size of 1 block is 1 megabyte; in the screenshot above, a normal transaction “occupies” 370 bytes. It takes about 10 minutes to generate 1 block. This means that about 2,600 transactions can be confirmed in 10 minutes. But there are actually much more of them.

On the same website blockchain.info you can see the size of the mempool (mempool – queue) of the network. This is the volume of all transactions that are awaiting confirmation.

In total they occupy over 100 megabytes. This means that less than 1% of transactions will be confirmed within 10 minutes. In total, their processing will take 10x100=1000 minutes or almost 17 hours. And this is assuming that any new transactions suddenly stop taking place on the BTC network.

The global solution to this situation is to increase the block size. This is exactly why it was held. It involves optimizing the use of memory for storing transaction data, and should prepare the network for further modifications (increasing the block) through a soft fork. Segwit2x, which included a hard fork (hard division of the blockchain) and an increase in the block size to 2 megabytes, was cancelled.

What will happen to the money?

One thing is for sure - your money will not disappear from you anywhere. There are two scenarios here:

• Wait until your transaction receives the required 2 confirmations;
• Take some measures to push it through.

The first option does not require any action from you. You know that transaction verification is available on blockchain.info and some other services, and you can look at its status from time to time by entering the identifier into the search. However, the waiting time can last for days, and in extreme cases, weeks.

And even if you are in no hurry to transfer, at some stage you will have to take action. We will talk about the main methods of acceleration below.

How long to wait for Bitcoin transaction confirmation

Some services indicate how long to wait for confirmation. But these numbers rarely have anything in common with reality. You can independently calculate the transaction confirmation time. To do this, you need to pay attention to the Fee per byte line.

The double spend method depends on the wallet you choose. Typically used by Bitcoin-Core or Bitcoin Knots users. To implement this method, you need to close Bitcoin Core and restart it in CMD ( command line) using the –zapwalletettxes command, having previously removed the mempool.dat file from the wallet directory.

After this, carry out the transaction again, but with an adequate commission. In this case, you need to intercept it, or rather combine the “input” of the old translation with the new one. To do this, in Bitcoin-Core, in the INPUT tab, select the old transaction and add another input from another transaction so that it covers the commission.

CPFP

CPFP is short for child pays for parent. This method is designed for situations where the sender has created a new transaction with bitcoins that they “conditionally” received from another transaction that has not yet been confirmed. In this case, in order to carry out the operation, it is necessary to pay a commission for that same unconfirmed transaction.

To do this, you need to go to the Wallet section (Settings -> Options -> Wallet), check the Spend unconfirmed change and Enable coin features fields.

After that, click send and work again with the Inputs section. Indicate yourself (yours) as the recipient, enter the amount that was previously sent to you and check the subtract fee amount box. Below, set the commission amount through Custom, and not through Recommended.

It is much easier to deal with a stuck unconfirmed transaction in the Electrum wallet. There is a re-sending function with an increased commission - replace-by-fee. However, it will only work if the Replaceable checkbox was checked during the initial sending.

Accelerators and “pushers”

Mining pools also speed up transactions – ViaBTC, AntPool. To speed up a transaction through ViaBTC, just go to the Tools section on the pool website and select Transaction Accelerator. To speed things up, simply enter the transaction ID and solve the captcha. The effectiveness of this method is controversial.
There are also many pool aggregator sites online, ViaBTC and AntPool. Example - perenosi.com. And Telegram created an acceleration bot - @FastTXbot. The bot aggregates pushes through AntPool automatically.

More more ways acceleration you can find in our article:

How to protect yourself from frozen transactions

First of all, you need to understand what affects the speed of transaction confirmation. A influences it shows the time of the transaction, the selected commission and the “path” of the bitcoins you send. Does not affect the number of bitcoins being sent and the wallet from which you are sending them.

If you received 10 bitcoins through 10 transactions of 1 bitcoin, then the transfer of these 10 bitcoins in bytes will be much larger than the transfer of 100 bitcoins that you received from 1 address. This is an example of the “Path” of sent bitcoins. It’s the same when sending – the more addresses, the higher the commission. If you need to send BTC to multiple recipients, then combine transactions into one and “fork” it through Input.

The key value is the size of the commission per 1 byte. Before sending bitcoins, look at the mempool's performance and check the average network fees. You can view commission figures on BitcoinFees.

If the mempool is empty, then even a transfer with a small penalty will go through - the simple law of supply and demand works here. Miners process transactions because better offers are rare. The ideal time is when China and Asia are sleeping. That is, in the European first and second time zones during this period it is evening (6-10 hours).

With proper work with the mempool, wallet and data on the average commission indicators, you can quickly conduct transactions and save at the same time.

Now you know why a bitcoin transaction is not confirmed, how to track it, and how to confirm it using various methods.

So, summary:

1. An unconfirmed transaction is a transaction that, after being sent, for some reason was not added to the block.
2. To speed up the transaction, you can use the Double Spend method, CPFP, Replace-by-fee, or special accelerators.
3. To protect yourself from freezes, you need to set the correct commission and take into account the time of the transaction.