Why does it take so long to confirm?

[vn10vn]

I want to make a trade, I sent btc to my account on an exchange, and it got 1 confirmation but then nothing, so its still pending.
I've been waiting more than an hour. Why does it take so long to confirm payments in the chain?

[Kluge]

On average, it'll be included in a block (confirmed the first time) within ten minutes, with each confirmation thereafter taking an average of ten minutes, though this can easily run into 40-50 minutes in unlucky times (on the flip-side, you can also see a transaction confirmed 6 times within ten minutes, too). If it took an hour to be included in a block, there's a good chance the transaction queue is bogged down from heavy use due to the current price volatility and you might want to consider including higher fees with your transactions.

To deeper penetrate "why," though - it's because confirming a block is a semi-random process to prevent cheating in mining. If you mean "why" relative to other cryptos, well... that'll take longer to answer, because there are both drawbacks and benefits to choosing 1m target conf times over 10m, and the same for 10m over 1h. Short answer is "it's considered near-optimal by TPTB."

[Pobre]

The general confirmation time is 10minutes(if you have paid the transaction fee), nowadays sometimes the mining of the blocks slow down due to the increase in the difficulty level, so sometimes your tx may take up to 1hour to confirm. To make the confirmations fast you can add a higher tx fee like some 0.001BTC.

[PerrythePlatypus]

The general confirmation time is 10minutes(if you have paid the transaction fee), nowadays sometimes the mining of the blocks slow down due to the increase in the difficulty level, so sometimes your tx may take up to 1hour to confirm. To make the confirmations fast you can add a higher tx fee like some 0.001BTC.

The increase in difficulty does not really result in slower blocks, difficulty is adjusted according to hashrate. Highly impossible that there will be a sudden significant slow In block generation due to lower sudden hash rates as ASICs are shipped at a fast rate. Transaction fee of 0.0001 is already enough. After getting one confirmation, any other block generated will result in another confirmation.

[Pobre]

The general confirmation time is 10minutes(if you have paid the transaction fee), nowadays sometimes the mining of the blocks slow down due to the increase in the difficulty level, so sometimes your tx may take up to 1hour to confirm. To make the confirmations fast you can add a higher tx fee like some 0.001BTC.

The increase in difficulty does not really result in slower blocks, difficulty is adjusted according to hashrate. Highly impossible that there will be a sudden significant slow In block generation due to lower sudden hash rates as ASICs are shipped at a fast rate. Transaction fee of 0.0001 is already enough. After getting one confirmation, any other block generated will result in another confirmation.

I meant that as the difficulty increases, people start getting less pay for more work and thus many people have been leaving the mining of the bitcoin that leads to the decrease in the hashrate.

[PerrythePlatypus]

The general confirmation time is 10minutes(if you have paid the transaction fee), nowadays sometimes the mining of the blocks slow down due to the increase in the difficulty level, so sometimes your tx may take up to 1hour to confirm. To make the confirmations fast you can add a higher tx fee like some 0.001BTC.

The increase in difficulty does not really result in slower blocks, difficulty is adjusted according to hashrate. Highly impossible that there will be a sudden significant slow In block generation due to lower sudden hash rates as ASICs are shipped at a fast rate. Transaction fee of 0.0001 is already enough. After getting one confirmation, any other block generated will result in another confirmation.

I meant that as the difficulty increases, people start getting less pay for more work and thus many people have been leaving the mining of the bitcoin that leads to the decrease in the hashrate.

If the hash rate ever decrease, the difficulty would readjust itself. There are a lot of ASICs being shipped and coming online where electricity are cheaper. The hash rate will not decrease significantly, since there is only some miners going offline, those new ASICs coming online can easily take the place of those and even increase the hashrate.

[Sonny]

The general confirmation time is 10minutes(if you have paid the transaction fee), nowadays sometimes the mining of the blocks slow down due to the increase in the difficulty level, so sometimes your tx may take up to 1hour to confirm. To make the confirmations fast you can add a higher tx fee like some 0.001BTC.

The increase in difficulty does not really result in slower blocks, difficulty is adjusted according to hashrate. Highly impossible that there will be a sudden significant slow In block generation due to lower sudden hash rates as ASICs are shipped at a fast rate. Transaction fee of 0.0001 is already enough. After getting one confirmation, any other block generated will result in another confirmation.

I meant that as the difficulty increases, people start getting less pay for more work and thus many people have been leaving the mining of the bitcoin that leads to the decrease in the hashrate.

Indeed, difficulty has been increasing for more than a year, and the difficulty adjustment is lagging behind (average block time is a bit lower than 10 min even after difficulty adjustment).

[byt411]

The general confirmation time is 10minutes(if you have paid the transaction fee), nowadays sometimes the mining of the blocks slow down due to the increase in the difficulty level, so sometimes your tx may take up to 1hour to confirm. To make the confirmations fast you can add a higher tx fee like some 0.001BTC.

The increase in difficulty does not really result in slower blocks, difficulty is adjusted according to hashrate. Highly impossible that there will be a sudden significant slow In block generation due to lower sudden hash rates as ASICs are shipped at a fast rate. Transaction fee of 0.0001 is already enough. After getting one confirmation, any other block generated will result in another confirmation.

I meant that as the difficulty increases, people start getting less pay for more work and thus many people have been leaving the mining of the bitcoin that leads to the decrease in the hashrate.

Indeed, difficulty has been increasing for more than a year, and the difficulty adjustment is lagging behind (average block time is a bit lower than 10 min even after difficulty adjustment).

Exactly. Also, if it isn't a big amount, 1 Confirmation is enough.

[tsm]

I never really understood, because sometimes my transaction are within seconds or mins at most.

But the other day, my transaction was literally past the 1hr mark.. like wtf? 

So seeing this explained a bit, kinda makes sens but I still dont get it lol. 

[byt411]

I never really understood, because sometimes my transaction are within seconds or mins at most.

But the other day, my transaction was literally past the 1hr mark.. like wtf? 

So seeing this explained a bit, kinda makes sens but I still dont get it lol. 

Basically, it's because things are never perfect and exact.
1 Confirmation is enough for payments of small quantities.

[tsm]

So I guess .1 is small?

I guess anything 1 btc below is slow as hell.  Cause I waited for my .1 bet and came in so late.

[byt411]

So I guess .1 is small?

I guess anything 1 btc below is slow as hell.  Cause I waited for my .1 bet and came in so late.

No it's not. 1 confirmation for .1BTC should be enough. You were just unlucky, the miners didn't find blocks for a whole hour.

[DolanDuck]

I want to make a trade, I sent btc to my account on an exchange, and it got 1 confirmation but then nothing, so its still pending.
I've been waiting more than an hour. Why does it take so long to confirm payments in the chain?

After a transaction is broadcast to the Bitcoin network, it may be included in a block that is published to the network. When that happens it is said that one confirmation has occurred for the transaction. With each subsequent block that is found, the number of confirmations is increased by one. To protect against double spending, a transaction should not be considered as confirmed until a certain number of blocks confirm, or verify that transaction.

The classic bitcoin client will show a transaction as "n/unconfirmed" until 6 blocks confirm the transaction. Merchants and exchanges who accept bitcoins as payment can set their own threshold as to how many confirmations are required until funds can be considered valid. When potential loss due to double spending as nominal, as with very inexpensive or non-fungible items, payments can be considered confirmed as soon as it is seen on the network. Most exchanges and other merchants who bear the risk from double spending require 6 or more blocks.

There is nothing special about the default, often-cited figure of 6 confirmations. It was chosen based on the assumption that an attacker is unlikely to amass more than 10% of the hashrate, and that a negligible risk of less than 0.1% is acceptable. Both these figures are arbitrary, however; 6 confirmations are overkill for casual attackers, and at the same time powerless against more dedicated attackers with much more than 10% hashrate.[1]
Coins generated aren't considered confirmed by the Bitcoin protocol for 100 blocks. It is advisable to wait some additional time for a better chance that the transaction will be propogated by all nodes. The classic bitcoin client won't show generated coins as confirmed until the 120th block.

Source: https://en.bitcoin.it/wiki/Confirmation

[Gimmelfarb]

i've waited about 90 minutes before for a single confirmation. it doesn't happen often, though. sometimes i get 2-3 confirmations within only a few minutes. but those times where a single confirmation takes over an hour -- very frustrating.

[PilotofBTC]

i've waited about 90 minutes before for a single confirmation. it doesn't happen often, though. sometimes i get 2-3 confirmations within only a few minutes. but those times where a single confirmation takes over an hour -- very frustrating.

What I've seen happen is that an output spends unconfirmed inputs. So, even thought the transaction paid the correct fee, the underlying inputs didn't. So, those inputs are talking longer to confirm which slows down the outputs that spent them. I've seen this a few times spending from Coinbase. I think they need to clean up there implementation and spend older inputs. Perhaps they just aren't keeping enough BTC in their hot wallet which is causing this, but that is just supposition.

[HarHarHar9965]

i've waited about 90 minutes before for a single confirmation. it doesn't happen often, though. sometimes i get 2-3 confirmations within only a few minutes. but those times where a single confirmation takes over an hour -- very frustrating.

What I've seen happen is that an output spends unconfirmed inputs. So, even thought the transaction paid the correct fee, the underlying inputs didn't. So, those inputs are talking longer to confirm which slows down the outputs that spent them. I've seen this a few times spending from Coinbase. I think they need to clean up there implementation and spend older inputs. Perhaps they just aren't keeping enough BTC in their hot wallet which is causing this, but that is just supposition.

sometimes if you watch for the next block, though, it literally takes an hour or more for the next block to be found. so it isn't about unconfirmed inputs.

[byt411]

i've waited about 90 minutes before for a single confirmation. it doesn't happen often, though. sometimes i get 2-3 confirmations within only a few minutes. but those times where a single confirmation takes over an hour -- very frustrating.

What I've seen happen is that an output spends unconfirmed inputs. So, even thought the transaction paid the correct fee, the underlying inputs didn't. So, those inputs are talking longer to confirm which slows down the outputs that spent them. I've seen this a few times spending from Coinbase. I think they need to clean up there implementation and spend older inputs. Perhaps they just aren't keeping enough BTC in their hot wallet which is causing this, but that is just supposition.

sometimes if you watch for the next block, though, it literally takes an hour or more for the next block to be found. so it isn't about unconfirmed inputs.

Variance. It's supposed to be every 10 minutes, but nothing is perfect.

[DannyElfman]

gosh yeah i remember bitcoin was crashing HARD and i was sending some coin to an exchange to panic sell and then it took over 2 hours for 6 confirms! by then it was already bouncing so i did not sell.

[Fiora]

So I guess .1 is small?

I guess anything 1 btc below is slow as hell.  Cause I waited for my .1 bet and came in so late.

No it's not. 1 confirmation for .1BTC should be enough. You were just unlucky, the miners didn't find blocks for a whole hour.

Damn, I was going to say isnt .1 big? But that unlucky part, does that happen a lot? I`m new to all this so every input would help.

How often does this happen when you have to wait for a whole hour?

Or would he has to enter .11 or something?

[ShameOnYou]

So I guess .1 is small?

I guess anything 1 btc below is slow as hell.  Cause I waited for my .1 bet and came in so late.

No it's not. 1 confirmation for .1BTC should be enough. You were just unlucky, the miners didn't find blocks for a whole hour.

Damn, I was going to say isnt .1 big? But that unlucky part, does that happen a lot? I`m new to all this so every input would help.

How often does this happen when you have to wait for a whole hour?

Or would he has to enter .11 or something?

When this happens, it is not because of the fee. No matter how big of a fee was included in the transaction, sometimes miners just don't solve a block for a long time -- like an hour or more. Other times you might get two blocks in 5 minutes. It doesn't happen often in my experience.