Difference between revisions of "Difficulty"

From Bitcoin Wiki
Jump to: navigation, search
m (Min/max confusion)
(How soon might I expect to generate a block?: link to existing hardware page, rather than nonexisting bitcoin_miners page. another wanted-page down.)
Line 34: Line 34:
 
* 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.
 
* 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).
 
* 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.
+
** [[Mining Hardware Comparison]] has some stats that may help you predict what you could get.
 
* Visit a calculator or perform the maths yourself,
 
* Visit a calculator or perform the maths yourself,
 
** http://www.alloscomp.com/bitcoin/calculator.php
 
** http://www.alloscomp.com/bitcoin/calculator.php

Revision as of 07:49, 26 December 2010

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).
  • Visit a calculator or perform the maths yourself,
  • Remember it's just probability! There are no guarantees you will win every N days.

This article uses content from the old wiki. The list of contributors to the old page is available here.