I have an application where I pay users in bitcoins (microtransactions). I am also starting to use Bitcoin core.

What I want: Pay the minimum possible as fee of a custom transaction (1 input and x outputs). I need to pay the minimum because this difference is very important to make my app viable.

I saw that here are different costs/byte. And I see that 0 fee transactions can take forever. But my doubt is that if I pay a minimum of 1 to 10 Satoshis/byte, could the transaction be stucked for ever? or it will spent as maximum 240 min (as the page shows right now I know it can vary).

I also "don't care" about the transaction time spends to reach its destination (to be confirmed) as much I would like 5 days more or less to confirm.


  1. Can it take forever if I pay the minimum or it will also be but in some days.
  2. What minimum of fee / byte do you recommend me?

Thank you for reading! If you don't understand something, please make me know and I'll try to explain better.

1 Answer 1


10 satoshis/byte would have gotten you a confirmation in five days for big parts of the past three months:

enter image description here [via https://core.jochen-hoenicke.de/queue/#3m, filter by 10-20 sats/byte]

Yet, I'm afraid that you cannot rely on getting a confirmation within five days at 10 satoshis/byte.

In the past three months, there were e.g. two weeks in August, where only a few blocks had transactions with <10 sats/byte. It's very likely that you would have gone without confirmations for sixteen days. Earlier this year from early May to mid of June, you would not have gotten any confirmation at all for six weeks.

Also, please think about your users' experience. When they end up with a large number of very small unspents, it will be uneconomic for them to spend them: a big portion would get eaten up by fees, at higher fees they would be unable to make any payments at all.

Unfortunately, since the cost of transactions is in relation to the blockchain space transactions require to get confirmed, the relative cost is significantly higher for micropayments than for larger sums. I would highly recommend looking either at off-chain solutions or other blockchains.

  • Hello, thank you for your answer. So I can pay more proportion for the transaction, what would you recommend (sat/byte) to place? Extra info: the transaction will be bulk transactions with 1 input and 5 (for now, will be bigger with the time) outputs, and each output of a minimum of 30000 Satoshis. in*180 + out*34 + 10 plus or minus 'in' so that will be a 360+-1 bytes. I could pay more if needed but what I really want is to secure that transactions doesn't get stuck. Thank you again!
    – Alberto
    Commented Sep 27, 2017 at 14:59
  • You definitely shouldn't go below 30,000 satoshis. If a user wants to spend from that, it's 148 for the input alone, which even at 1 sat/byte is already 5% of the value. At 10 sat/byte they pay almost 50% for the input alone.
    – Murch
    Commented Sep 27, 2017 at 15:51
  • Oops, sorry, my comment about 30,000 satoshis didn't make a lot of sense, because I was off by a factor of ten. I now had my first cup of coffee, and what I said would be true at 3,000 satoshis. 30,000 seems reasonable to me at current fee rates. I think you might want to go with 1-10 satoshis/Byte but then also use replace by fee to bump the fees if transactions don't confirm within a few days. If fees go back up to the 100+ sat/B range, these inputs will become pretty costly to spend though.
    – Murch
    Commented Sep 27, 2017 at 16:16
  • Okay! I think that I'll try with 10 sat/byte. Could you help me to learn what I need to know how exactly works bitcoin core? (Create wallet and make a 1 to much transaction) I think that I know more or less how it works but if you help me by sharing any helpful link I would appreciate it very much :)
    – Alberto
    Commented Sep 27, 2017 at 16:36
  • Hey, I think that this might help you: bitcoin.org/en/developer-documentation, else you might want to just ask another question. :)
    – Murch
    Commented Sep 28, 2017 at 6:11

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