CPFP with '2' parents transaction?

[trainchoo55]

Hi, I made the common mistake of inputting fees that are too low (40 sats/byte) on 2 consecutive transactions, and i'm trying to do a CPFP transaction to push through the 2 stuck transactions in one go

Below are the 2 unconfirmed stuck transactions. If I do a 3rd CPFP transaction to move 'B2' into another address, would all 3 transactions go through if I put a high enough fee?

1st Txn input->output: A -> A1 (exch wallet) + A2 (own wallet)
2nd Txn input->output: A2 (own wallet) -> B2 (own wallet)

Thanks!

[1715052349]

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[1715052349]

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[ranochigo]

Depends. I didn't quite get the whole transaction part. Are your transactions all linked together? Is the second unconfirmed transaction spending the unconfirmed output from the first transaction?

If so, you can just create a CPFP transaction from B2 (transaction must include the output from the second transaction) with a sufficient fee. If not, you have to ensure that your CPFP transaction is both spending the output from the first transaction and the second transaction.

If you'd like, PM me the transaction IDs and I'll see if you're doing it right. If you're making your own raw transaction, feel free to PM me to check as well.

[trainchoo55]

Yes the 2nd unconfirmed transaction is spending the unconfirmed output from the 1st transaction (A2).

The unconfirmed output from the 1st transaction (A2) is just the change returning to my wallet.

Thanks alot! I'll use electrum to do the CPFP transaction from B2

[bob123]

Yes, all of your 3 transactions would go through when performing a CPFP.
But you have to make sure that you chose a fee which is high enough for all of your 3 transactions.
You can estimate an fee here: https://bitcoinfees.earn.com/.
According to this site currently a fee of 400 sat/B will give you a 'pretty' high chance of getting it confirmed within 3 hours.
So in your case you'd have to chose a fee of 1200 sat/B to get your transactions through within this timeframe (90% chance).

[kahc]

Hi, I made the common mistake of inputting fees that are too low (40 sats/byte) on 2 consecutive transactions, and i'm trying to do a CPFP transaction to push through the 2 stuck transactions in one go

Below are the 2 unconfirmed stuck transactions. If I do a 3rd CPFP transaction to move 'B2' into another address, would all 3 transactions go through if I put a high enough fee?

1st Txn input->output: A -> A1 (exch wallet) + A2 (own wallet)
2nd Txn input->output: A2 (own wallet) -> B2 (own wallet)

Thanks!

We need to know many inputs/outputs the grandparent and parent transaction have, and total fees paid before we can calculate the fee needed for the child transaction.

[Thirdspace]

1st Txn input->output: A -> A1 (exch wallet) + A2 (own wallet)
2nd Txn input->output: A2 (own wallet) -> B2 (own wallet)

if it's simple txs like you mentioned above, why not drop the 2nd tx
and then resend again with higher fee enough to cover both the 1st and this modified 2nd tx
it would be something like trying to double spend and CPFP tx at the same time
even better if "A" is your UTXO, you could just drop the those 2 txs and resend over to the exchange
are you sending/receiving? but it seems A here is an address/utxo owned by the exchange

[HCP]

I think you might be a bit confused about what the OP has done... OP has sent two transactions:

Transaction One, Sending to Exchange, low fee:

Input A -----> Output A1 (Exchange Address)
             |
             |---> Output A2 (Change Address)

Transaction Two, low fee:

Input A2 ------> Output B (Receive Address, different wallet)


Now, the OP is attempting to clean up these two transactions, by doing a 3rd transaction... which is a CPFP that will cover all three transactions. The formulas for this will be something like:

Total Fee required for third transaction = (Transaction One bytes + Transaction Two bytes + Transaction Three bytes) * current recommended fees
Fee rate for third transaction = Total fee required for third transaction / transaction three bytes

Given Transaction#1 was 1 inputs, 2 outputs, it should be around 226 bytes, Transaction#2 had 1 input, 1 output = 192 bytes... Transaction#3 size? difficult to say, depends on how much BTC is in Output B and can it cover the fees... if so, it could theoretically be 1 input, 1 output...

https://bitcoinfees.earn.com/ is currently estimating 500 sats/byte... so :

(226 + 192 + 192) * 500 = 610 bytes * 500 = 305,000 sats required fee... so transaction#3 should be sent with 0.00305000 BTC total fee... or 305,000 sats / 192 bytes = 1589 sats/byte fee (0.01589 BTC/kb)

[Thirdspace]

I think you might be a bit confused about what the OP has done... OP has sent two transactions:

Transaction One, Sending to Exchange, low fee:

Transaction Two, low fee:

Input A2 ------> Output B (Receive Address, different wallet)

why not drop the 2nd tx
and then resend again with higher fee enough to cover both the 1st and this modified 2nd tx
it would be something like trying to double spend and CPFP tx at the same time

exactly why I said the above post.
if his 2nd tx was between his wallet addresses, he could drop it and re-send (RBF or Double Spend)
why make 3rd tx and waste fee on it, if it can be done by doing something on the 2nd tx

so transaction#3 should be sent with 0.00305000 BTC total fee... or 305,000 sats / 192 bytes = 1589 sats/byte fee (0.01589 BTC/kb)

small typo? should be 1589 sats/byte fee == 0.01589 mBTC/kb)

[HCP]

exactly why I said the above post.
if his 2nd tx was between his wallet addresses, he could drop it and re-send (RBF or Double Spend)
why make 3rd tx and waste fee on it, if it can be done by doing something on the 2nd tx

Which would be a great idea... if you could "drop" transactions... which you can't... Because, as we call know... Bitcoin transactions cannot be cancelled or reversed. Once broadcast, there is no sure-fire/easy way to simply drop a transaction.

Sure, you can attempt double-spends (easy enough to create, very hard to actually broadcast as usually rejected by the majority of nodes)... RBF would be great if the original wallet sending Transaction#2 supported RBF and had marked the transaction as RBF, then sure, RBF Trans#2.

small typo? should be 1589 sats/byte fee == 0.01589 mBTC/kb)

no... I'm pretty sure if you multiply 1589 sats/byte by 1000... you get 1,589,000 sats/kB... which is 0.01589 BTC/kB

[Thirdspace]

Sure, you can attempt double-spends (easy enough to create, very hard to actually broadcast as usually rejected by the majority of nodes)... RBF would be great if the original wallet sending Transaction#2 supported RBF and had marked the transaction as RBF, then sure, RBF Trans#2.

now, it would be a good idea for him to tell us the real txids and addresses involved here
so we can assess the actual condition and give out possible solutions

small typo? should be 1589 sats/byte fee == 0.01589 mBTC/kb)

no... I'm pretty sure if you multiply 1589 sats/byte by 1000... you get 1,589,000 sats/kB... which is 0.01589 BTC/kB

oops... you're right   I'm the one who made mistake, I didn't look closely on kB