Miners work on finding blocks but don't sent anything until they find the block.
Considering that, how can sites like bitcoincharts.com display a graph of the network hash rate?
1
- 2If I flip a fair coin repeatedly, and tell you that I found 1 billion heads, it's (practically) statistically certain that I flipped the coin very nearly 2 billion times. The same sort of extrapolation can determine the total network power based on the success rate.Tim S.– Tim S.2014-01-30 21:53:30 +00:00Commented Jan 30, 2014 at 21:53
Add a comment |
2 Answers
The hashrate can be calculated from the expected rate of finding a block (144 a day), the actual rate of finding a block and the current difficulty.
So let's calculate the average hash_rate for a single day:
expected_blocks = 144 difficulty = 11187257.461361 # this is on May 22nd 2013 blocks_found = 155 # Also May 22nd 2013 hash_rate = (blocks_found/expected_blocks*difficulty * 2**32 / 600) The reason we use a day to average out the hash_rate is that taken block by block the variance would be really high and we would not get anything meaningful.
According to WolframAlpha this gives us an averagge hash_rate for the 22nd May 2013 of 86.19 THashes/s. Numbers of course may vary depending on how you chose your interval, which appears to be the reason numbers don't match with the ones on Blockchain.info
- 1I know this answer was given 5 years ago, but why 2**32? I'm presuming it has something to do with the 256-bit hashing function used, but some clarification would be awesome :)glowkeeper– glowkeeper2018-10-04 13:34:44 +00:00Commented Oct 4, 2018 at 13:34
- 1@glowkeeper see bitcoin.stackexchange.com/a/30225/60443JBaczuk– JBaczuk2018-11-14 20:39:46 +00:00Commented Nov 14, 2018 at 20:39
- Thanks, @JBaczuk! Looks good! I should probably check that answer against mine (bitcoin.stackexchange.com/questions/79774/…), but I'm currently knee-deep in code, so I'll report back later, once I've done some back-of-the-envelope-calc's :)glowkeeper– glowkeeper2018-11-16 09:53:49 +00:00Commented Nov 16, 2018 at 9:53
The network hash rate can be statistically inferred from the difficulty and the rate at which blocks are found. It's just a more complex version of the fact that if you know that someone is flipping coins and heads comes up 800 times an hour, they're flipping about 1,600 coins an hour.
