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Revision as of 05:11, 24 December 2010 by Theymos (talk | contribs) (Min/max confusion)
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See also: target

What is "difficulty"?

Difficulty is a measure of how difficult it is to find a new block compared to the easiest it can ever be.

How often does the difficulty change?

Every 2016 blocks.

What is the formula for difficulty?

difficulty = maximum_target / current_target

(target is a 256 bit number)

What is the current difficulty?

Current difficulty, as output by BitCoin's getDifficulty.

What is the maximum difficulty?

The maximum difficulty is roughly: maximum_target / 1, which is a ridiculously huge number (about 2^224).

The actual maximum difficulty is when current_target=0, but we would not be able to calculate the difficulty if that happened. (fortunately it never will, so we're ok.)

Can the difficulty go down?

Yes it can. See discussion in target.

What is the minimum difficulty?

The minimum difficulty, when the target is at the maximum allowed value, is 1.

How soon might I expect to generate a block?

(The eternal question.)

  • Any one grinding of the hash stands the same chance of "winning" as any other. The numbers game is how many attempts your hardware can make per second.
  • You need to know the difficulty (above) and your khash/sec rate (reported by the client).
    • bitcoin_miners has some stats that may help you predict what you could get.
  • Visit a calculator or perform the maths yourself,
  • Remember it's just probability! There are no guarantees you will win every N days.

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