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/ How to cancel or replace an unconfirmed transaction

How to cancel or replace an unconfirmed transaction

Published 29 August 2023
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Unconfirmed transactions have not been validated on the network within 24 hours by validators or network miners and are not anchored in the blockchain's data mass. Network participants must validate every cryptocurrency transaction.

Causes of transaction problems

Transactions are not validated for several reasons. If the transaction fee is not paid in full or is below the allowable limit. The lower the transaction fee amount, the lower the chances that the transaction will be validated online.

Also, the transaction is not confirmed due to significant network congestion at any given time. The more popular the cryptocurrency, the higher the load on the network can be.

Transactions sometimes exceed block size limits. If a transaction exceeds the block size limit, then its miners do not include it in the block. In this case, the network is unable to process the transfer in time.

Sometimes the transaction remains unconfirmed if the protocol is old. Old protocols often do not support new network functionality. Also, old protocols are often incompatible with new software (software) required for a node to function fully.

In addition, older protocols may not be able to process the new type of transaction properly.

It is worth noting that sometimes novice users confuse unconfirmed and incomplete transfers on the network. An incomplete transaction has not been completed on the network due to some problem on the network.

What to do if a transaction is not completed

If a transaction is not completed, there are several ways to fix it. In particular, it is necessary to specify the correct address of a purse, and if it is specified incorrectly, then the transaction will not be completed.

You need to check if the internet is working well. Due to a faulty connection in the network, the transaction is simply not transferred to the network. It is necessary to check the quality of the Internet and see if there is a blockage on the part of the firewall.

You should also find out, if possible, what time of day the network is operating at its maximum load. Many networks operate at their peak load in the morning and evening hours, so it is best to send the transaction at a time when the network is not overloaded to make it complete.

How do I track the execution of a transaction in the blockchain?

For example, you can use a blockchain browser (such as Etherscan) to check the execution status of a transaction in the Ethereum blockchain. Enter the hash of the transaction and the sender/receiver addresses to see the transfer status in the blockchain.

A transaction in the Ethereum blockchain is technically initiated by an external account holder (crypto wallet holder), and each action of debiting one account and crediting other changes the state of the blockchain.

In the blockchain browser, the executed operation is indicated by a green checkmark (as in the photo example). Unexecuted transactions are highlighted in red.

The change occurs explicitly on the Ethereum Virtual Machine (EVM). Ethereum's transactions are broadcast throughout the network and to every node in the blockchain. Any node can broadcast a request to execute a transaction on an EVM.

What to do to replace or cancel an unconfirmed transaction

There are several ways to replace or cancel unconfirmed transactions.

One of them is a method such as RBF (fee replacement).

  • RBF (Commission Substitution)

Its essence is that if the transaction is not confirmed, a new transaction is created, and it will replace or cancel the previous one. However, the new transaction will have a higher fee.

The user will have to pay more for it, cancel the previous transaction, and return the associated funds to his wallet account.

In turn, this method has several versions.

Full RBF assumes the following: the user pays a fee for the new and the previous transactions. In this case, the transaction is then confirmed in the network.

Opt-in RBF - before making a payment, the user is sent permission from the protocol if he is ready to make the payment.

First-Seen-Safe RBF - this protocol replaces the payment if a new transaction is performed on an output identical to the first one.

Delayed RBF - the protocol allows network participants to include the payment in the block with a lower fee to reduce the cost to the user and only then conducts a cancellation or replacement transaction.

An important nuance - RBF is possible to engage using wallets. But not all of them do. We recommend that you research whether the wallet has this ability before you choose a wallet.

There is also the CPFP (child pays for parent) method.

  • CPFP (child pays for the parent)

The essence of this method is the following. If a transaction is not confirmed and the user wants to cancel or replace it, then he must create a new transfer (child transfer). He spent the cryptocurrency he received in the previous transfer (parent transfer).

The child transfer will pay a higher fee, indicating to network members that they must mine the first transfer to mine the second one later. The customer will then be able to get a new transaction.

There is another way in which it is possible to cancel or replace an unconfirmed transfer. This is a method of double-spending. In some ways, it is similar to RBF.

The user can try to complete the transaction again, and only he will pay a higher fee. Members of the network will take it and will spend it.

Some mining pools provide a service to replace or cancel an unsupported transaction. However, the customer must pay an additional fee to the mining pool that maintains the network. He will then include the transaction in the next block.

These are the ways that currently exist that allow users to cancel, or if necessary replace, an unconfirmed transfer on the blockchain. Perhaps there will soon be other ways to perform these blockchain transaction manipulations.


Thus, users can cancel or replace unconfirmed transactions on the network. To do this, they can use the above methods. One can choose the one that is most financially preferable to the customer.

It is worth noting that it is possible to prevent unconfirmed transactions with a simple technique of paying higher fees to the network. As a rule, network members process and confirm transactions with higher fees than others.

If a customer has the financial capacity to do so, they can confirm transactions with higher fees. In this case, he will not need to replace, or cancel an unconfirmed transfer, wasting time and money.

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EXEX LTD. Registered Number: 232147
Seychelles, Mahe, Victoria, Frances Rachel Street, Sound & Vision House, Suite 1