Transaction confirmation projections. Likelihood to get into the next n-blocks.

[RogerR]

Is there is way to find out how much one should pay in transaction fees to get included in the next few blocks?

I paid 0.001BTC and have missed out on the last 5 blocks. Perhaps some form of projection function would be helpful here.

[Stephen Gornick]

Is there is way to find out how much one should pay in transaction fees to get included in the next few blocks?

I paid 0.001BTC and have missed out on the last 5 blocks. Perhaps some form of projection function would be helpful here.

Many transactions require no fee and are included in the next block, so paying a fee would almost certainly cause it to be included in the next block or two.

Are you sure it didn't make it into a block?  Check Block Explorer:
 - http://www.blockexplorer.com

If the transaction is still queued up for inclusion, it will likely appear here:
 - http://bitcoincharts.com/bitcoin/

[RogerR]

It finally got confirmed in the 6th block. Kind of made me worry there for a bit.

Perhaps there were just really a lot of transactions going through at the same time which paid more. But considering the business nature of those transactions, it would be good to have a way to roughly calculate how much one needs to pay to have a 50% chance to be included in the next block, 70% in the next 2, etc...

Unless I miss out on some important technical details, it shouldn't be all that difficult to come up with a rough prediction model that incorporates the latest transaction history - considering the transparent nature of all transactions. Maybe there even is a tool for that sort of stuff available already? Hence me asking.

[Stephen Gornick]

It finally got confirmed in the 6th block. Kind of made me worry there for a bit.

Just to make sure that you are describing the problem correctly, understand this:

The classic bitcoin client will show a transaction as "n/unconfirmed" until 6 blocks confirm the transaction

- http://en.bitcoin.it/wiki/Confirmation

So there is no amount of fee that will cause at transaction to "confirm" any earlier than 6 blocks.  

What I thought you were describing is that the transaction did not even get included into a block right away.  That can happen unless a fee is paid.  Before a transaction is included in a block, it likely will appear here:
  - http://www.bitcoincharts.com/bitcoin

The reason there's no "price versus time" chart is because, for the most part, all transactions get into the next block or two regardless of the fee paid.  If no fee was paid and the transaction is a low priority transaction, then it could end up queued.  There already is a solution for that though -- next time make sure to pay the minimum transaction fee when sending payment and the problem is solved.  Keeping your Bitcoin client current may be useful so that if a fee is necessary, the client will make an accurate fee suggestion.
  - http://en.bitcoin.it/wiki/Vocabulary  (see "priority").

At some point, when transaction fees become more important to miners, the transaction fee could affect how soon a miner includes the transaction.  At the present and near-term future (next years or so maybe?), it isn't an issue, as far as I'm aware.   [related: http://forum.bitcoin.org/index.php?topic=14571.msg196574#msg196574 ]

[JoelKatz]

To summarize: If you define "confirmed" as being at least six blocks deep in the chain, no amount of fees will allow a transaction to confirm until at least six blocks are generated after the transaction is initiated. This will typically take just a bit less than an hour.

Except for very large transactions, once a transaction has 2 confirmations, it can be considered confirmed for all practical purposes. And once a transaction is visible in the list of unconfirmed but valid transactions, it is safe from everything but an intentional double-spend attack on the part of the sender.