Bitcoin Forum

I was wondering, what is the smallest fee, I can use, to still have my transaction confirmed?

I am currently on a site, where "things" can be bought, for a few satoshi's {less than 3000 satoshi} BUT the problem come in, that to get this transaction confirmed, you have to spend more Satoshi's than what the digital item was worth.  ^frown^

So this negate the statement, that bitcoin are best for micro transactions like this.

If you leave no fee, it will never be confirmed. Or there might be a possibility

So as a guideline, I need to know, what minimum fee, will guarantee a confirmation of the transaction?

0, it might just take a while (as in: up to a week) till a miner will include your TX in a block.


With the way the standart fee currently works and the value of bitcoin, its indeed not good for microtransactions.


No fee can guarantee a confirmation, but it would be very unlikely if a TX would not be included in the next block with standard fee (10k satoshi / kbyte). A lower fee (e.g. 1k satoshi / kbyte) will lead to less miners that will include your TX in a block, but if you have a little time any miner would do and there are still some out there with enough power to make a block that accept 0 fee TX.

if the transaction is more than 5500+ satoshi if you pay fee or not it must be confirmed. minimum fee is usually 10.000 satoshi.

Wrong! I tried it by sending 0.05 BTC and it didn't work when not including a fee. There is no minimum fee, you can even send a 0 fee transaction but it will hardly get a transaction, sometimes it will be broadcasted from many days and just drop out. It is better to send a transaction with 0.001BTC and if you can't then, 0.000001BTC. Lower than that would make the transaction hard to get a confirmation. ::)

  ~~MZ~~

I think the average miners set as the TX fee to include in blocks is 10,000 satoshi's and anything lower than that would take more time than the average 10 minutes for a block.

The standard fee is 0.0001 btc per KB, but you can send transaction without fee as well. It will be confirmed if it has a high enough priority (please read https://en.bitcoin.it/wiki/Transaction_fees#Reference_Implementation).


For micro-transaction, it is better to do it offchain.

Well, next question then, based on the previous response.

What is offchain? I am using blockchain.info wallet, and I think it's online all the time. ^frown^

Offchain transactions are transactions that are not processed and recorded in the bitcoin blocks.
For example, you can send bitcoin from your Coinbase account to my Coinbase account. There will be no public bitcoin transaction going through but just only a record on the Coinbase's internal database.

I have sent micro-transactions for 0 fee on blockchain.info but you have to make sure your coins have been there for a few days already. If it does not work, as it happened to me a few times, you get it back but it can take a few days. BTC is not made for micro-transactions and the fees are a way to try not to have them otherwise the blockchain would be even bigger than what it is now.
Maybe suggest the website to accept litecoins or darkcoins, or others, as they are more suitable for those small transactions

it can be zero fee, if you keep them long enough in the wallet.

As others have already explained, free transactions do get confirmations as long as the coins are old enough. If you want to play safe and make sure the transaction will be confirmed within reasonable time, just don't change your default wallet fee setting and pay the fee your wallet client asks for.

Standard fee for any transaction is 0.00010000 btc. As for the micro-transactions. its priority in the blockchain is very low to be confirmed as fast as other transactions on the blockchain. Micro-transactions usually take more time to confirm or not getting confirmed at all.

What is minimal amount of coins in micro-transaction?

https://bitcoin.org/en/developer-guide#non-standard-transactions
If a transaction has an output smaller than 546 satoshi, it will be considered non-standard and will not be relayed by Bitcoin core 0.9.0+.

But I think it can also be relayed if the miner disables default settings! ::)


  ~~MZ~~

True, and also not every nodes on the network run on the latest protocol version.
That's why some of those dust spamming transactions were able to be relayed across the network and were eventually confirmed.

So does the miners determine on their own, if they want to mine for blocks with transactions without fees? Or are these transactions bundled in with other transactions with fees?

Thanks for the answers so far, at least now I know, to put a minimum of 10k Satoshi's for small transactions.

Yes, they can even decide to not include any TX at all.


Usually not. Most transactions rely on other transactions that are allready confirmed, sometimes however it happens that TX A is not yet confirmed (e.g. because no fees) and TX B that spends the outputs from TX A pays a fee. In that case it makes sense for a miner to confirm A because only then B can be confirmed. Usually they would confirm both in the same block, to benefit from the fees of TX B.


Or you can wait and hope. I am currently waiting [1] for a feeless TX to go through. Its day 3 now and it might never confirm without further tricks. In general it is not wise to do this. Better pay your fees if you want your coins to move fast ;)


[1] https://www.blocktrail.com/tx/10fd41c4c86ae68c6382fd9ec0f92625b70a03d03d8ae1c4a564aa3ea03b570c

But has this way of "considering the total tx fee of a series of transactions" been implemented by the miners yet?
I have heard of this for a very long time, but I couldn't find if it is still a proposal or if it is already working.

Not sure how the miners handle this internally, but usually when people spend unconfirmed change and pay a regular or normal fee both TX get confirmed within the next or very few blocks.

is that even worth it?

For the miners? Sure, its not like we are anywhere close to the 1 MB blocksize limit, so there is enough room. Any TX that pays and gets confirmed is money in the wallet. There is no downside or at least I am not aware of one currently.

Thanks for your info.



It is good for the general bitcoin users as well.

Say if someone send you 0.05 btc but for some reason didn't attach a 0.0001 fee, you may need to wait for a few days without luck, contact the sender, explain the problem, persuade and teach him to create a double-spend transaction with fee.
Or you could simply send that unconfirmed 0.05 btc to yourself with a 0.0001 fee to solve all the problem all by yourself.

A follow up question, based on the first question.

Say, I own a faucet, and every Sunday, I want to make micro payments to say 3000 users. What would the best method be, to pay these users, and to have the least amount of transactions/miner fees?

I see many faucets, with a withdraw limit of 5000+ Satoshi and I can just imagine, that the transaction fees, would nulify the gain or reduce the profits, if it was done individually.

Do I pay less, if it's batched together, and what technology or wallet, would make the payment the cheapest for massive micro transactions? ^Grin^ 

Micro transactions do confirm even without a fee, but usually within a couple of days or even weeks (and sometimes they don't). Miners usually don't 'prioritize' transactions that doesn't include a tx fee. You have to wait until that transaction confirms, or it may not confirm at all.

teach me how to do these 2 please or give a link :)

faucets use https://www.microwallet.org/ they can send even 1 satoshi and it is offchain transaction check the API page for more info

That process involve trusting a third party with your BTC. If they decide to run away, you may lose all your BTC. You could make a withdrawal limit of 5500 satoshi for example and send the payments every week by batches. The transaction fees can be reduced.

If you don't want to trust a third party and use offchain transaction, the best option is to group the payments together and make a few huge transactions like what moonbit does https://blockchain.info/address/12Zdr4CqdaLCngZJgLWVLYbuWNc2NNKKk5?filter=1