How many shares need to be processed on average before a block is found?

I know that "luck" can be a huge factor which is why it's not quite as simple as that.

I ask because I'm starting my own pool (www.btcpoolman.com). I only have three people on it at the moment, but we've mined about 100K shares in the past week or so. Assuming I sustain this, how long will it be before I will get a block?

I found http://www.bitcoinx.com/profit/ yesterday, which says that it'll take one year and 138 days to find a block based on 1.2 GHash/s (which is roughly what I do when soloing).

Failing that, what should I do if I'm currently mining at the above rate?

3 Answers 3


When mining in a pool you are simply looking for simpler blocks than those that are used in the network itself. Let's say you are mining in a pool that counts difficulty 1 shares. That means to find share you have to complete 2^32 hash operations. Since difficulty is defined as the ratio between the current target and the maximum (as in easiest) target, each increment in the difficulty doubles the number of hash operations you'd need to find a share. Hence the probability of a share also being a block is:

share_difficulty / block_difficulty

since the current difficulty (29th of May 2013) is 12'153'411.7098 the chances of a share of difficulty 1 being a block is 1/12'153'411.7098, and the expected number of shares until a block is being found is again 12'153'411.7098. Notice that in the last step we are talking about an expected number of shares. As mining is a random process there is no guarantee of finding a block in finite time.

  • Thanks for the clarification. So would you suggest that i solo, join a pool or continue trying to make my own pool?
    – Andy
    Commented May 29, 2013 at 15:57
  • That strongly depends on your constraints, can you sit for months or years without getting a block, and then get lucky one day that pays off for all the time, or do you need a regular, but smaller, income. The first case is the solo mining option, the second is the pool mining option. From a reward point of view they are identical (except fees in the case of a pool), just the reward distribution is different.
    – cdecker
    Commented May 29, 2013 at 19:55
  • hi cdecker, thanks for this. For solo, it just seems like it'll take too long, my other concern is that Bitcoin difficulty will only get harder, so i fear that i would be mining for all eternity and not get anything.
    – Andy
    Commented May 30, 2013 at 11:08
  • That being said, I've setup my own pool with a friend (btcpoolman.com) i'm practically soloing though this but we're pooling our resources. Any idea on how i can get people to my new pool?
    – Andy
    Commented May 30, 2013 at 11:10
  • Attracting people to your pool is just like selling any given thing. Find out why you stick out, are your fees competitive, do you have a track record of zero downtime, can people find your pool if they are looking, are your payouths higher or comparable. In short why are you better than the other pools? The site design looks nice, nice colors and friendly feel. Doesnt look geeky at all.
    – Filip
    Commented Aug 27, 2013 at 17:12

On average, as many as the difficulty currently is.

  • 2
    To expand, at the moment you could expect 12 million shares to be submitted, on average, before a block is found. Commented May 29, 2013 at 13:48
  • 2
    Assuming the shares are at difficulty 1 - many pools don't do that.
    – Nick ODell
    Commented May 29, 2013 at 17:58

Currently, in the year of 2015, the month of July, and the pool of GHash.io, (which is currently the largest mining pool in the world,) the number of shares amount to ~25 BILLION. We, with the speed of ~6.40 PHashs/s, do an entire block in anywhere from a few hours, to several days, depending on the difficulty.

I'm not sure if this is the answer you are looking for, but this may help you put things into perspective.

The sincerest of luck to you good sir.

  • GHash.io is one of the smaller pools now.
    – Claris
    Commented Jul 12, 2015 at 4:44
  • Downvoted: As this answer is strongly tied to the current time. Therefore, it will soon outdate and hence is not very useful. Please try to answer questions in a way so that the main points remain useful timelessly, such as in cdecker's answer. Content such as your current state can be added as an example or visualization of the main points, but in itself don't suffice.
    – Murch
    Commented Jul 13, 2015 at 13:50

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