Duration of new block to confirm and include transactions

[Cookdata]

I learnt that the time to create a new block in bitcoin takes an average time of 10 minutes but I don't understand what happened yesterday when I carried out a transaction.

I sent some BTC and my transaction was successfully included in block 738344 and it was confirmed on May 29, 2022, 12:31 AM UTC.
The previous block 738344 before my transaction was first confirmed on May 29, 2022, 12:30 AM UTC which was just 1 minute apart but the next block 738345 after my transaction was first confirmed on May 29, 2022, 12:53 AM UTC and the difference between that and mine was 22 minute, why is it like that?

If 6 blocks will take 1 hour with an average of 10 minutes for first confirmation, what will happen when this happens, is this an anomaly because other blocks are similar to this with time variation or there is no standard duration for new blocks.

[1715048563]

1715048563

[jackg]

The target tries to maintain there being anew block every 10 minutes. People who've actually done the maths say its between 8 or 9 minutes.

There are a few things faced here:
1. Block finding is based off random numbers and the target can be easy or hard to get (essentially, a miner that mins a block in 1-2 minutes just got lucky with their random number generator for the nonce).
2. Hash rate mostly increases as doesn't decrease much, every block mined when the previous target was set was set on an average of that - this will add to that as well as miners might also time when to turn new devices on to be nearer the time the target gets reset so they can get a higher reward/more blocks.

[Charles-Tim]

A bitcoin transaction can take less than 2 minutes, it can take 3 minutes, it can take 9, 10, 15 or more or less minutes, it can even take 30 or more or less minutes, but taking 10 minutes on average.

If mining hashrates increase before difficulty adjustment, you can see more of blocks getting mined before 10 minutes and transaction in the process also getting confirmed.

If the mining hashrates decrease before the difficulty adjustment, there will be many transactions getting confirmed after 10 minutes.

Mining difficulty is adjusted every 2016 blocks, that should take approximately 2 weeks.

[ranochigo]

The block frequency follows a Poisson distribution and the time between the block follows an exponential distribution. This means that while the average block time is 10 minutes, the probability of the blocks being shorter than 1 minute is 9.516%, which is still fairly significant. The reason for this is because the golden nonce (or the parameters that corresponds to a valid block) is found at random, and hence a random variable.

Though an increase in the hashrate can result in an increased probability (and vice versa), the main factor is just that the probability of this happening is relatively high.

[odolvlobo]

I learnt that the time to create a new block in bitcoin takes an average time of 10 minutes but I don't understand what happened yesterday when I carried out a transaction.
...
If 6 blocks will take 1 hour with an average of 10 minutes for first confirmation, what will happen when this happens, is this an anomaly because other blocks are similar to this with time variation or there is no standard duration for new blocks.

The time between blocks is random, but the average is 10 minutes. The average for 6 blocks is one hour. The average for 144 blocks is 1 day.

The difficulty is automatically adjusted every 2016 blocks to keep the average at 10 minutes (based on how quickly previous blocks were added).

[nc50lc]

I learnt that the time to create a new block in bitcoin takes an average time of 10 minutes but I don't understand what happened yesterday when I carried out a transaction.

To fully understand it, you need to learn at least these two things:

• learnmeabitcoin.com/technical/mining
• learnmeabitcoin.com/technical/target

As a summary, the "target" is a number which is set to be higher or lower to maintain the 10-minute block average.
Miners are trying to get a hash with lower value than the target, each try can be the winning block, be it within a minute, ten (on average) or even an hour, it's unpredictable.

[pooya87]

I learnt that the time to create a new block in bitcoin takes an average time of 10 minutes

It is mining a new block that takes 10 minutes on average not creation of a new block.

Mining is a process that is very similar to brute forcing, you have to compute a lot of hashes until you find the "correct" one. Just like brute forcing a password you start from somewhere and the first try may be the correct one (hence finding the next block in matter of seconds) or you may continue trying many passwords until you eventually find the correct one.

https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch10.asciidoc#proof-of-work-algorithm

[NotATether]

Mining difficulty is adjusted every 2016 blocks, that should take approximately 2 weeks.

Actually, the epoch length will be much less than 2 weeks if there is a sudden increase in hashing power i.e. decrease in confirm time, and vice versa (the epoch will last much longer if signiicant hashpower suddenly goes offline during the epoch. This is what usually happens because miners generally don't leave vast quantities of miners idle).

[hosseinimr93]

8-9 minutes? Are you talking about mean block time of all-time or certain time period? I'm certain it's 9.4 minutes during genesis block until 2018.

I just made a simple calculation.
Till now 738567 blocks have been mined. These blocks have been mined in 4894 days, 18 hours, 40 minutes.
The overall average block time has been 9 minutes and 33 seconds.

[o_e_l_e_o]

You can see the average block time for every 2016 block retargeting period since the genesis block here: https://btc.com/stats/diff

And you can see the stats for the current retargeting period using this site: https://www.bitrawr.com/difficulty-estimator. If you convert the current pace from a percentage to a fraction and then divide 600 seconds by this number, it will tell you the current average block time. For example, at time of writing the current pace is 101.3413%. 600/1.0134 = 592 seconds. So the current average block time is 9 minutes and 52 seconds.

[stompix]

I just made a simple calculation.
Till now 738567 blocks have been mined. These blocks have been mined in 4894 days, 18 hours, 40 minutes.
The overall average block time has been 9 minutes and 33 seconds.

This is comparable to the jumps the price has made, we've seen it going 10000x time up but that doesn't mean we're going to see that happening again, same with the hashrate growing, when ASICs hit the market, from 2013 till late 2014 the average was well below 9 minutes, with a lot of periods ending with even 6 minutes and a half on average.
That won't be possible anymore unless you also have a large shutdown before some are getting plugged in again, to keep a 5% increase each period you will need right now about 100k asics, and each time this requirement will grow exponentially.

As  o_e_l_e_o mentioned, break it down to 100k or yearly batches and you're going to see that the deviation is going down