What is the minimum transaction fee?

[MaTachi]

The other day I made a transaction of 0.01 BTC and instead of the default transaction fee 0.0005 BTC I entered 0.0002 BTC. The transaction went fine and I believe it took as long to arrive as with the default transaction fee.

What is the minimum transaction fee I can pay? And what could possibly happen if it is too low?

[Cyberdyne]

The minimum fee possible is 0, however it depends on many different factors.

I suggest reading this article: http://bitcoinfees.com

[CryptoCat]

The minimum transaction fee is 0BTC.
This transaction just takes longer (from a few hours to a few days).

[MaTachi]

The minimum transaction fee is 0BTC.
This transaction just takes longer (from a few hours to a few days).

Is there a risk that it never arrives? Could I respend it if it doesn't arrive?

[CryptoCat]

The minimum transaction fee is 0BTC.
This transaction just takes longer (from a few hours to a few days).

Is there a risk that it never arrives? Could I respend it if it doesn't arrive?

No, it just takes some tiem
And you can't double spent.

[Birdy]

Is there a risk that it never arrives? Could I respend it if it doesn't arrive?

I have to disagree with Cryptocat:
Yes, there is a chance that it will be stuck for a very very long time, especially if you are sending a tiny amount of BTC.
It is possible to double-spend the Bitcoins and the first one to be accepted in a block will come through.
(the same client won't let you make a second transaction, you could import the private key to a second one or use some program to edit a local client)

[MaTachi]

The minimum transaction fee is 0BTC.
This transaction just takes longer (from a few hours to a few days).

Is there a risk that it never arrives? Could I respend it if it doesn't arrive?

No, it just takes some tiem

Is the transaction time possible to predict based on the transaction fee? And is it possible that a transaction with a fee of 0 BTC gets handled right away if there is a low number of transactions in the network?

[Birdy]

Is the transaction time possible to predict based on the transaction fee? And is it possible that a transaction with a fee of 0 BTC gets handled right away if there is a low number of transactions in the network?

The transaction time is based on the integration of your transaction into a newly mined block.
Miners will prefer transaction with a higher fee (+some other factors like coin age, amount of Btcs,datasize), so they will include them first.
If there is a low number of transactions your transaction without a fee may be handled right away.

Btw: usual transaction fee of the qt-client is now 0.0001 (unless the Btc amount is made up by a lot of tiny transactions. If you collect dust from the free BTC sites and try to send all that the transaction will have a very big datasize)
You should be fine by using that fee.

[CryptoCat]

You should listen to Birdy  

I sometimes sent some BTC from my blockchain wallet without fees.
They took some time, but they always arrived.

[legitnick]

The fee amount usually varies, but its never very high and usually isnt over 1%

[Prophet]

1 satoshi per kb should bé enough to start à little experiment, then up it to 1000 satoshis see what happens.

[Cheeseheaven]

If i am correct anything under 0.01 is about 0.0005 a fee
If you have a lot of small satoshi causing it to have a lot of memory or something you could get a fee of 0.0195 or something (meh o.o)

[medinscot]

The fee amount usually varies, but its never very high and usually isnt over 1%

if transaction = 0.01BTC and fee = 0.0005BTC, fee = 5%

[bg002h]

The default answer is now ฿0.0001/kb for Bitcoin-qt 0.8.2 and up. But, in reality, miners charge whatever they want. If evil mega-Corp buys a ton of ASICs (or miners collude) and controls nearly all the hashing power....they set the true minimum fee.

0.8.2 Release notes
===================

Fee Policy changes
------------------

The default fee for low-priority transactions is lowered from 0.0005 BTC
(for each 1,000 bytes in the transaction; an average transaction is
about 500 bytes) to 0.0001 BTC.

Payments (transaction outputs) of 0.543 times the minimum relay fee
(0.00005430 BTC) are now considered 'non-standard', because storing them
costs the network more than they are worth and spending them will usually
cost their owner more in transaction fees than they are worth.

Non-standard transactions are not relayed across the network, are not included
in blocks by most miners, and will not show up in your wallet until they are
included in a block.

The default fee policy can be overridden using the -mintxfee and -minrelaytxfee
command-line options, but note that we intend to replace the hard-coded fees
with code that automatically calculates and suggests appropriate fees in the
0.9 release and note that if you set a fee policy significantly different from
the rest of the network your transactions may never confirm.

[jackjack]

The minimum transaction fee is 0BTC.
This transaction just takes longer (from a few hours to a few days).

Is there a risk that it never arrives? Could I respend it if it doesn't arrive?

No, it just takes some tiem
And you can't double spent.

You can double-spend

[CIYAM]

You can double-spend

Whilst it is *possible* it is actually in practice rather difficult to do (I tried once after making a huge mistake with fees doing a raw tx).

Any node that has seen the first tx will ignore the "double spend" attempt - making it virtually impossible to then do so after only a few seconds across much of the network.

[jackjack]

You can double-spend

Whilst it is *possible* it is actually in practice rather difficult to do (I tried once after making a huge mistake with fees doing a raw tx).

Any node that has seen the first tx will ignore the "double spend" attempt - making it virtually impossible to then do so after only a few seconds across much of the network.

Indeed, you can't do this immediately but the saying "you can't double spent" leads newbies to fear/feeling scammed/posting aggressively in the tech forum.

So:
Yes we can.
But you'll have to use the search function to find the guide and to wait a bit.

[rme]

Actual recomended fee is 0.0001BTC

[CIYAM]

Indeed, you can't do this immediately but the saying "you can't double spent" leads newbies to fear/feeling scammed/posting aggressively in the tech forum.

I agree with the sentiment (too much FUD spread around in general) but at the same time it should be understood that the entire *premise* of Bitcoin was to "solve the double spending problem" (so IMO not really a useful thing to tell people that you "can double spend" as it then leads people to infer that Bitcoin is *fundamentally flawed* which is isn't).

[jackjack]

Indeed, you can't do this immediately but the saying "you can't double spent" leads newbies to fear/feeling scammed/posting aggressively in the tech forum.

I agree with the sentiment (too much FUD spread around in general) but at the same time it should be understood that the entire *premise* of Bitcoin was to "solve the double spending problem" (so IMO not really a useful thing to tell people that you "can double spend" as it then leads people to infer that Bitcoin is *fundamentally flawed* which is isn't).

Indeed, I used the same words than the post I replied to
That would be nice to find another word for this

For newbies: double-spending means here 'replace an old, stuck transaction which isn't accepted in the blockchain with a new one'