I'm testing some functionality on the testnet and I'm having problems with the transactions priority.

According to the technical info, a transaction that has not enough priority should have a fee of 0.00001 BTC/kb (1000 Satoshi), but when I try to broadcast my transaction using a RPC call to my local full node, I get an insufficient priority error:

{u'message': u'66: insufficient priority', u'code': -26}

For example, the following transaction has 3 inputs and 2 outputs:


what according to bitcoinfees will have a size of:

148 * 3 + 34 * 2 + 10 = 522 bytes

and it also has a transaction fee of 0.00001 bitcoins, but trying to broadcast it will raise the error shown above.

Does anyone knows what could I've been doing wrong?

  • What version of Bitcoin Core is your full node running? The minimum fees were different in earlier versions. Nov 20, 2015 at 15:30
  • Bitcoin Core Daemon version v0.11.2.0-g7e27892
    – sr_gi
    Nov 20, 2015 at 15:41
  • I'm thinking that maybe it could be because of bitcoin dust. Does any output of less than 0.01 BTC require a fee of 0.00001? I mean, if I'm building a transaction with three inputs, two of them of less than 0.01 BTC, and a total size of less than 1KB, would it need 2*0.00001 BTC because of the two small inputs?
    – sr_gi
    Nov 23, 2015 at 11:27
  • At this point I think the best way to try to understand it might be to single-step the source code, either mentally or with a debugger. Nov 23, 2015 at 14:51

1 Answer 1


I've found what was wrong. It seems that technical info is not up to date to the current Bitcoin Core version ( Since version 0.11 (12 July 2015) the minimum relay fee is 5 times bigger (from 1000 Satoshi to 5000) so the transaction has not enough fees to be relayed.

Here you could find a discussion about the topic.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.