Bitcoin Forum

Hi, I'm running into trouble trying to send BTC from my wallet at https://blockchain.info. I can receive BTC, but  can't send . Last night I tried to send 2 BTC and today less but both tries ended up with the same  red "Unconfirmed" tab . Further more today I received my 2 BTC  from last night back into my account, meaning transaction was unsuccessfull.
 Today after I tried again to send few BTC from the wallet I saw my transaction on "latest transaction page" almost immediately, but didnt appear on  http://bitcoincharts.com/bitcoin/txlist/ , as it didn't appear last night in my other try.
  So I'm wondering what am I doing wrong here?

Try paying the network fee?

https://blockchain.info/wallet/faq :

"What fees do you charge?

This service is now free of charge/p> "

He is talking about the Transaction fees (https://en.bitcoin.it/wiki/Transaction_fees)

My bad, ty!

I'm quite familiar with the inner workings of Bitcoin, but there's one question that's bugged me from the very beginning.

How does one know how much transaction fee to pay?

It seems weird to me that you have to basically take a guess. If you guess too high, you waste money. If you guess too low, your transaction might sit in limbo, perhaps indefinitely. Is there a science to calculating exactly how much fee to pay if you want your transaction confirmed within X amount of time?

0.0005 is the standard fee, regardless of the amount sent. Larger amounts of coin sent (>1) might not require a fee at all depending on the coin's age.

See, that's the thing. I know the age of the input is a factor in the formula. Say I want to send 0.5 BTC. Should I pay the fee or not? I've never paid a fee using Bitcoin to date, and I've sent amounts as small as 0.1 BTC. I tend to sit on my balances for a while, though, so I'm probably satisfying the age requirements. But my point is, I don't know when I've met the requirements for sending a transaction without a fee. The client does not provide any visibility into which unspent inputs it's going to pick to construct a new outgoing transaction.

The client will automatically calculate and warn you if a tx fee is needed. I'm too lazy now to dig out the underlying determination formulae, but I remember there's one. Small transactions count as <0.01 if I'm not wrong.

It is complicated and likely to change.

What the Satoshi client does is pretty strange.  Other clients don't do the same thing and there is no guarantee on what miners will chose to include or nodes will rebroadcast.  This is kind of as it needs to be.  One of the attack vectors on the network is to generate too many stupid transactions that just cycle money around.  If that starts to happen people will tweak the fee structure to make that expensive or not worth it for the person doing it.  And we don't really know what those will look like until it happens.

Example, lets say everyone uses 0.0005 as a standard transaction fee.  That is enough where sending thousands of transactions is unappealing long term.  However, if bitcoins end up being 0.02 USD each then that transaction fee is so small that someone might DoS the network with transactions for fun.  So it needs to be flexible and somewhat undefined.

I just voluntarily pay a small fee, if there is more required the client tells me.  There is a very valid point made.  Say I want to empty a wallet.  You have to get lucky that you pick the right amount so that the fee is the exact amount left.