Bitcoin’s Hash Rate / Difficulty History

Updated 4/12/2018

According to, we are on track for a 14%+ drop in Network Difficulty this difficulty epoch.

This will the biggest drop in difficulty since November 1, 2011–7 years ago. That particular drop was 18%, the largest in history. The preceding difficulty epoch saw what was the largest drop in history up to that point, 13.09%. It still holds the record for 2nd biggest drop in history, but that record is now being challenged.

The third biggest drop in history, 11.59%, happened in the difficulty epoch immediately prior to the first halving at block 210,000 (shown in yellow in the image below). It is a distant 3rd however, and will lose its spot by the end of this epoch.

Interesting things to note:

  • Of the 273 completed difficulty epochs, 38 have seen negative difficulty change, or, about 13.9% of all epochs
  • Of the 38 negative changes, 7 have been by less than 1%, 13 by over 5%, and only 3 times by more than 10%.
  • Difficulty is just as volatile as price, with an average difficulty change of +12.85% with a standard deviation of change at a whopping 23.3%
  • Between the 67th and the 75th epochs in late 2011, the difficulty dropped 8 consecutive times, resulting in a 42% drop in Network Hash Rate over that period. The two biggest drops in history also occurred consecutively during that run, a 13% drop, followed up by an 18% drop
  • Similar to the large drop in hash rate ahead of the first halving, a drop in difficulty of 5.43% occurred before the 2nd halving too.
Bitcoin Network Difficulty History

Bitcoin Evangelist. BEng MEngSc MBA

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