<p>Update for everyone who stumbles up on this question. There is a paper that shows why it is hard to figure out the actual fork rate.</p>

<p><a href="https://i.sstatic.net/FwEpT.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/FwEpT.png" alt="xxx"></a></p>

<p>it's from this paper "Echoes of the Past:
Recovering Blockchain Metrics From Merged Mining" </p>

<p><a href="https://eprint.iacr.org/2018/1134.pdf" rel="nofollow noreferrer">https://eprint.iacr.org/2018/1134.pdf</a></p>

CC BY-SA 4.0
2019-02-05T22:50:14.880Z
It's worth adding that increases in block propagation speed (esp in the last 2.5 years) have further suppressed the propagation of stale blocks.  Blocks which are stale before the source ever announced them don't propagate, so speeding up the network causes you to see fewer of them and things like BIP152 and fibre have made the network a lot faster.
G. Maxwell
CC BY-SA 4.0
2019-02-05T17:21:11.707Z
2019-02-07T19:04:12.733Z
2019-02-07T19:04:12.733Z
davidDavidson
<p>Both of the links in the previous two answers aren't working.
Historic data (both, until March 2014) can be viewed on the internet archive.
The last snapshot from blockexplorer.com: <a href="https://web.archive.org/web/20130313092352/http://blockexplorer.com/q/reorglog" rel="nofollow">https://web.archive.org/web/20130313092352/http://blockexplorer.com/q/reorglog</a> </p>

<p>The last snapshot from blockchain.info can be found in a similar way (stackexchange doesn't allow me to post more than 2 links, since I don't have enough reputation...). </p>

<p>An updated information, that unfortunately contain few details, is available in Organ Ofcorti's blog.<br>
See, for example, <a href="http://organofcorti.blogspot.com/2014/05/may-11th-2014-weekly-hashrate.html" rel="nofollow">http://organofcorti.blogspot.com/2014/05/may-11th-2014-weekly-hashrate.html</a> , Table 2.
The information is presented per week, in an image (not as text - which makes it a bit harder to analyze).  </p>

CC BY-SA 4.0
2019-02-06T02:48:28.850Z
You can see in the chart above that more recent times (e.g. post height 403200, 2016-03) look a lot different than 2014, however.
G. Maxwell
CC BY-SA 3.0
2014-05-22T00:53:30.183Z
2014-05-22T00:53:30.183Z
Or Sattath
<p>Blocks are orphaned once in a while, roughly every few hundred blocks:</p>

<p><a href="http://blockchain.info/orphaned-blocks" rel="nofollow">http://blockchain.info/orphaned-blocks</a></p>

<p>There used to be a <a href="http://blockexplorer.com/" rel="nofollow">blockexplorer</a>-provided list of chain reorganizations which can occur upon such events (might become available again someday):</p>

<p><a href="http://blockexplorer.com/q/reorglog" rel="nofollow">http://blockexplorer.com/q/reorglog</a></p>

<p>These chain reorgs used to happen a few times per month.</p>

CC BY-SA 3.0
2013-01-03T12:52:29.753Z
The reorglog is not very indicative of blockchain forks or orphaned nodes as a reorg only happens if a fork happens *and* the node was expecting the other branch to be the winner. Therefore most forks are not detected as the node already chooses the correct block on which the longest chain will be built.
cdecker
CC BY-SA 3.0
2013-04-04T16:17:33.967Z
http://blockexplorer.com/q/reorglog gives a HTTP 404 error. Is there a new location where this information can be found?
Flow
CC BY-SA 3.0
2013-04-04T18:30:34.430Z
@Flow: the whole site seems to be down. Dunno when/if it will be back soon.
Stéphane Gimenez
CC BY-SA 3.0
2011-12-08T02:29:42.313Z
"not very often" is a relative term, and doesn't mean a lot to me. It would be worth providing a ball-park figure on this question.
Highly Irregular
CC BY-SA 3.0
2011-12-08T09:40:15.660Z
You can check that by using the link provided. They happened 3 to 9 times a month since July.
nponeccop
CC BY-SA 3.0
2011-12-07T16:06:49.470Z
2013-11-26T19:30:47.373Z
2013-11-26T19:30:47.373Z
Stéphane Gimenez
<p>How often do forks occur in the block chain? I'm interested in the small, one block forks that happen when two miners create a block at the similar time.</p>

<mining-theory><blockchain-fork><stale-block>
How often forks occur?
ThePiachu
# How often forks occur?

(Asked by: username_0 on 2011-12-07)

How often do forks occur in the block chain? I'm interested in the small, one block forks that happen when two miners create a block at the similar time.

**Tags:** mining-theory, blockchain-fork, stale-block


---

## 3 answers

### Answer by username_4 on 2011-12-07. Score: 6 | Accepted answer

Blocks are orphaned once in a while, roughly every few hundred blocks:

<http://blockchain.info/orphaned-blocks>

There used to be a [blockexplorer](http://blockexplorer.com/)-provided list of chain reorganizations which can occur upon such events (might become available again someday):

<http://blockexplorer.com/q/reorglog>

These chain reorgs used to happen a few times per month.

> **Comments:**
> **username_7**: "not very often" is a relative term, and doesn't mean a lot to me. It would be worth providing a ball-park figure on this question.  
> **username_8**: You can check that by using the link provided. They happened 3 to 9 times a month since July.  
> **username_5**: The reorglog is not very indicative of blockchain forks or orphaned nodes as a reorg only happens if a fork happens *and* the node was expecting the other branch to be the winner. Therefore most forks are not detected as the node already chooses the correct block on which the longest chain will be built.  
> **username_6**: http://blockexplorer.com/q/reorglog gives a HTTP 404 error. Is there a new location where this information can be found?  
> **username_4**: @username_6: the whole site seems to be down. Dunno when/if it will be back soon.  

---

### Answer by username_1 on 2019-02-05. Score: 3

Update for everyone who stumbles up on this question. There is a paper that shows why it is hard to figure out the actual fork rate.

[![xxx](https://i.sstatic.net/FwEpT.png)](https://i.sstatic.net/FwEpT.png)

it's from this paper "Echoes of the Past:
Recovering Blockchain Metrics From Merged Mining"

<https://eprint.iacr.org/2018/1134.pdf>

> **Comments:**
> **username_2**: It's worth adding that increases in block propagation speed (esp in the last 2.5 years) have further suppressed the propagation of stale blocks.  Blocks which are stale before the source ever announced them don't propagate, so speeding up the network causes you to see fewer of them and things like BIP152 and fibre have made the network a lot faster.  

---

### Answer by username_3 on 2014-05-22. Score: 2

Both of the links in the previous two answers aren't working.
Historic data (both, until March 2014) can be viewed on the internet archive.
The last snapshot from blockexplorer.com: <https://web.archive.org/web/20130313092352/http://blockexplorer.com/q/reorglog>

The last snapshot from blockchain.info can be found in a similar way (stackexchange doesn't allow me to post more than 2 links, since I don't have enough reputation...).

An updated information, that unfortunately contain few details, is available in Organ Ofcorti's blog.  
See, for example, <http://organofcorti.blogspot.com/2014/05/may-11th-2014-weekly-hashrate.html> , Table 2.
The information is presented per week, in an image (not as text - which makes it a bit harder to analyze).

> **Comments:**
> **username_2**: You can see in the chart above that more recent times (e.g. post height 403200, 2016-03) look a lot different than 2014, however.  

---

