I am developing a Bitcoin application, so I am sending a lot of "toy" transactions for testing, with 0 fees.

But it seems that those take forever to get confirmed. (Right now I am waiting 45 minutes for one transaction to get confirmed. Previously it was about 30 minutes.)

Is my suspicion right, or am I doing something wrong? How important is the fee for miners? Do they preferentiate?

Or am I doing something wrong (not broadcasting to enough nodes, maybe?)?

And do nodes, that aren't miners (with official client I presume), preferentiate to send around transactions with fees?

(edit: note that the question was written in 2012, when the blocks were still empty.)

  • Why would a miner waste time adding transactions to a block for a reward of essentially nothing? in fact one can argue that it wastes resources. Miners aren't in it to be nice to others, they're doing it to make money.
    – Daniel
    Commented Mar 24, 2017 at 14:49
  • Again this is question from 2012 when blocks were still empty and nobody cared about the fees very much and most money was from the rewards. (It only bubbled up, because I added up the note.) Commented Mar 27, 2017 at 21:17

4 Answers 4


It seems like there is some policy against free transactions in official client.

There are some anti-spam protections, which my toy transactions exactly meet (low transactions, recently accepted coins, etc)



  • 3
    Well, that would be it. Thanks for answering your question! To answer it further, miners do often accept only transactions with high enough fees. I expect this to only increase around December, when the non-fee block reward is halved. The clients, other than spam prevention, do not preferentially forward as far as I know.
    – Daniel H
    Commented Aug 20, 2012 at 4:42

The relationship between fee and confirmation time will change over time.

This chart provides a view of confirmation time for "fee" and "no fee": http://bitcoinstats.org/

However, the chart gives no information on the size of the fee paid. I'd like to see charts of:

  1. Fee Paid vs Confirmation Time
  2. (Transaction Size divided by Fee Paid) vs Confirmation Time.

Both these, especially the latter, are likely to show a stronger trend than the link I provided above, if/when we start hitting the size limit for blocks.

If anyone finds a site generating one of these, I'd appreciate it if you could provide a link!


Similar to you, I send a lot of small transactions to test my code. I find if I add a fee of a milli (0.001 BTC) they normally get in the next block but any less than that and you start having to wait.


Not sure if this is helpful, but this spreadsheet has fees and associated transaction times. I cant vouch for its accuracy Avg Confirmation Times with Fees Pd

Spreadsheet wth detail

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