Child Pays for Parent Failing

[Bitcoin Ben]

Hi,

I'm trying to increase the fee to get an unconfirmed transaction through.

Input Amount: 0.00546 mBTC
Output: blank
Fee for child: 0.00546 mBTC

No matter what I do, I get an error that says:
Cannot create child transaction:
The output value remaining after fee is too low.

What can I do here?

[Bitcoin Smith]

This means the fee for CPFP is exceeding the transaction value of the transaction and after the paying fee the actual output of the TX will be zero.

What can I do here?

Wait for the fee to drop and for the last few days its been crazy and I guess it will go on for a week or two like what happened earliers with ordinals. Also you can expect the fee to drop considerably at the weekend.

[Bitcoin Ben]

Yes, it looks like the total fee exceeds the other amounts.

The total fee is 0.06978 mBTC

What should I do in this situation?

[Orpichukwu]

Yes, it looks like the total fee exceeds the other amounts.

The total fee is 0.06978 mBTC

What should I do in this situation?

You can try closing and starting the transaction process from scratch, then you can use the custom process and programme how much you want your fee to be instead of using the default shown by the wallet that you are using. You can increase the fee to at least 80 Sats and let it roll. Maybe before morning you will get your transaction confirmed.
 
But then again, your transaction amount is really very low, so you should just consider leaving that transaction for now, as you will end up not going home with anything. You can increase the fee to at least 80 Sats and let it roll. Maybe before morning you will get your transaction confirmed.

[Bitcoin Ben]

Are you suggesting that I cancel the original transaction somehow?

If so, how can I safely do that?

[hosseinimr93]

Since you are doing CPFP and not RBF, I assume you are the receiver of an unconfirmed transaction. Am I right?

In CPFP method, you spend the fund you received in the unconfirmed transaction in a new transaction with high fee, so miners include both transactions (the unconfirmed parent and the child) in the same block.

The problem is now the value of unconfirmed output you are trying to spend is too low and that's not enough for paying the transaction fee.

What should I do in this situation?

You can send new fund to your wallet and use that for CPFP, but it seems that the value of the fund you have received is too low and it's not worth to do CPFP.

[Bitcoin Ben]

I have 2 transactions, and I think I sent one, and the other one I might be a receiver.

I'm willing to pay the current rates of 90 sats+

I just don't know how to do it.

[hosseinimr93]

I have 2 transactions, and I think I sent one, and the other one I might be a receiver.

It shouldn't be difficult to know whether you are the sender or the receiver. If the transaction is adding to your balance, you are the receiver and if it's deceasing your balance you are the sender.

If you are the sender and your transaction has been flagged as RBF, you can bump the fee.
If you are the receiver, you can use CPFP.

If the size of your unconfirmed transaction is less than 500 bytes, its fee rate is at least 10 sat/byte and it doesn't have any unconfirmed parent, you can submit your transaction to ViaBTC free accelerator. If you do so, your transaction will be included in the next block mined by them. They have around 10% of the total hash rate and it's estimated that they mine 1 block in every 100 minutes.


Can you share the transaction IDs? (Note that with doing so, you may harm your privacy. So, don't do that, if you worry about your privacy)

[Bitcoin Ben]

Thanks. I'm trying ViaBTC now.

[Bitcoin Ben]

If I'm willing to pay more for the transaction, I still don't understand how I can do that.

I have enough in the wallet to cover it, so I don't know why I'm getting the output value error

How do I get around this using the Electrum wallet?

[hosseinimr93]

I have enough in the wallet to cover it, so I don't know why I'm getting the output value error

As I already said, the value of the coin you have received is too low and it's not worth to use CPFP at all.
Do you really want to do CPFP and pay fee for a transaction in which you receive only 546 satoshi? Do you know that it's worth less than $0.2?

If you insist on doing so, you should make the CPFP transaction manually.  This means that you should spend the fund you have received in the unconfirmed transaction (along with another UTXO to cover the fee) in a new transaction with high fee.

[joniboini]

How do I get around this using the Electrum wallet?

Check out some guides related CPFP such as this one[1] if you must do so. You can also check the docs for Electrum to see how to do it[2]. While some images are no longer shown, you can still follow the text explanation. But as mentioned above, if the issue is not solved then you won't be able to do CPFP. Since you mentioned Electrum, do you use it to publish that transaction? Are you sure you don't enable RBF for that?

[1] https://bitcointalk.org/index.php?topic=5285192.0
[2] https://electrum.readthedocs.io/en/latest/faq.html

[Abdussamad]

You can do a manual CPFP transaction. Include the coin (unspent output) generated by the parent transaction as well as another unspent output from your wallet allowing you to raise the transaction fees. See the guide here:

https://bitcoinelectrum.com/how-to-do-a-manual-child-pays-for-parent-transaction/

[nc50lc]

I have enough in the wallet to cover it, so I don't know why I'm getting the output value error

For privacy reasons, Electrum will only use the related coins to the child transaction so it wont link your other UTXO with it.

The option you have is the "manual method" via coin control linked above.
The disadvantage is you'll have to manually compute the total fee of the child and parent transactions by yourself.

Computation is basic math though:
Before that, get the to-be-bumped (parent) transaction's size and absolute fee (electrum displays the size in bytes but it's actually already in vbytes, 'fee' is the total fee, not the 'fee rate')
For example: '250vbytes' and '0.00002500BTC' (2500satoshi)

• Firstly, Create the child transaction as instructed in the link and take note of the pre-computed size in the 'New Transaction' window but do not finish/send it yet.
• Secondly, to get your target fee rate the total size, get the sum of the parent and child's sizes, for example: '250vbytes' + '150vbytes' = '400vbytes'
• Thirdly, with your target total transaction fee rate, '50sat/vbytes' for example; multiply it with that total bytes to get the required absolute fee: 400' x 50 = '20000 satoshi'
  Then, Deduct the parent's absolute fee from the above to see how much you need to add to reach that target, for example: 20000sat - 2500sat = '17500satoshi'
• Finally, set that as the fee of the child transaction or a few sats more if the final size ends up higher, tick "Edit fees manually" in the setting icon (upper-right) to be able to set an absolute fee.

If I'm willing to pay more for the transaction, I still don't understand how I can do that.

Be careful on that though, since the transaction that you're trying to bump with CPFP may also have an unconfirmed parent (or more) with even lower fee rate that'll make your child transaction useless.
That's because your child transaction has to pay for those too to be able to bump the transaction that you're trying to bump.
So check if its input(s) are all confirmed or if unconfirmed, should have good fee rate.

[hosseinimr93]

The option you have is the "manual method" via coin control linked above.

This is right, but OP shouldn't do that.

The value of the coin OP received in the unconfirmed transaction is too low and it's not enough for covering the fee. Therefore, the fee required to be paid for the child transaction will be bigger than the value of that coin and OP would waste money on transaction fee.

Also, with adding another coin to be used as input of the transaction, OP would increase the transaction size and transaction fee.
Of course, this would act as consolidation of outputs, but it's not a good time for that as the network is so congested now.

[nc50lc]

The option you have is the "manual method" via coin control linked above.

This is right, but OP shouldn't do that.

You already informed him that but he's insisting, even willing to add another input with it.
So it may be important like his own non-rbf transaction imported from somewhere using the change's private key.
Without the TXIDs, we'll never know the whole story.

[khaled0111]

Input Amount: 0.00546 mBTC
Output: blank
Fee for child: 0.00546 mBTC

No matter what I do, I get an error that says:
Cannot create child transaction:
The output value remaining after fee is too low.

Is 0.00546 mBTC the "input amount" or the "output amount"?
If it's the "input amount" then you will not be able to broadcast the transaction even if you manage to create it. Other nodes will reject it as  any output amount smaller then 546 sats is considered a dust amount.

What wallet are you using? Because, afaik, Electrum will alow you to create the transaction but you will get a different error message when you broadcast it.

[hosseinimr93]

What wallet are you using? Because, afaik, Electrum will alow you to create the transaction but you will get a different error message when you broadcast it.

OP is using electrum.
You can see the same error message here in the source code of electrum: https://github.com/spesmilo/electrum/blob/master/electrum/wallet.py#L2219

To get that error, you should right click on an unconfirmed transaction, select "Child pay for parent", set the "Fee for child" to an amount which makes the "output amount" smaller than the dust limit and click "Ok".