how to analyse a stuck transaction using free, online tools

Today, i’m writing a short tutorial on how to analyse a stuck transaction using blockchain.info‘s block explorer. Blockchain.info’s explorer isn’t the best one out there, from time to time it has some bugs, but it’s one of the most used block explorers, so that’s why i chose this one to write up a short tutorial.

How to find out the reason why your transaction is stuck

  • find the transaction id from your stuck transaction… How to do this depends on your specific kind of wallet.
  • surf to blockchain.info, enter your transaction id in the search window (right top corner) and hit enter. A shortcut is to just enter https://blockchain.info/tx/{your tx id} in the address bar of your browser and hit enter.
  • Click on “Show scripts & coinbase”
blockchain.info Show scripts & coinbase
blockchain.info Show scripts & coinbase
  1. you can enter the txid directly in your browser’s address bar and hit enter
  2. click on “Show scripts & coinbase”
  • after you’ve clicked on “Show scripts & coinbase”, you should see a screen like this one:
blockchain.info detailed view
blockchain.info detailed view

Possible problems

  1. If you see a red [u] next to the input, it means there’s an unconfirmed parent… This is bad, since your transaction will only be able to confirm after the parent has been confirmed. This might be the reason why your transaction doesn’t confirm 😉
  2. if you see a red (spent) after (one of) the output(s), it means the output of your (unconfirmed) transaction has already been used for a new transaction. Needless to say, this new transaction will not be confirmed before your transaction is. This can’t be the reason why your transaction didn’t confirm… It is, however, the reason why the next person’s transaction didn’t confirm (yet).
  3. look at the size of the outputs… If there are outputs smaller than 0.000025, this might be considered as a dust output by some nodes, so it has a higher chance of being rejected. If it’s rejected by more nodes, it might not have propagated completely, so less miners might know about your transaction, lowering the chance for a confirmation.
  4. here you can see if your transaction is confirmed or not
  5. here you can see the fee per byte… Look at bitcoinfees.21.co to find out if your fee was/is high enough at this moment. If you used a substandard fee, this might be the reason why your transaction is stuck

other things that can go wrong: double spending the inputs of the unconfirmed transaction

double spent input
double spent input
  1. this transaction is labelled as a double spent, here you find the blockchain.info id of the transaction that spends the same inputs. If this other transaction has a higher fee/byte, your chance of getting a confirmation are slim. If the other transaction is already confirmed, your chances of being confirmed are allmost 0 (it would take an orphaned block and a lot of luck to solve this problem… If the double spend has 3+ confirmations, there is 0.0000000% chance of getting your transaction into a block)
  2. once again, a textual warning of a double spent transaction

Leave a Reply