Transaction priority



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?


Posted 2015-11-20T14:42:17.080

Reputation: 2 584

What version of Bitcoin Core is your full node running? The minimum fees were different in earlier versions. – Nate Eldredge – 2015-11-20T15:30:20.783

Bitcoin Core Daemon version v0.11.2.0-g7e27892 – sr-gi – 2015-11-20T15:41:08.087

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 – 2015-11-23T11:27:51.347

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. – Nate Eldredge – 2015-11-23T14:51:16.510



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.


Posted 2015-11-20T14:42:17.080

Reputation: 2 584