For example, how many times a month would you expect a 2 block reorg? What about for deeper reorgs?

  • Tezos doesn't have reorgs happen that often. So, 0 per month is the expectation. The protocol does not allow reorganizations longer than 5 cycles ago. It's an extremely rare phenomenon in Tezos. I believe the new tenderbake protocol will introduce 2-block finality.
    – utdrmac
    Jun 21, 2021 at 17:37

1 Answer 1


Basically reorgs do not seem to happen on mainnet, as far as I know.

However, theoretically they can happen. Using the analysis from this blog post, for an attacker having 20% of the total active stake, we get that currently (with Emmy+) 2-block reorgs may a priori happen around 8 times per month. With the new protocol Granada, which upgrades the consensus algorithm to Emmy*, such reorgs would only happen once every 90 years.

The raw data: probability of a fork of length 2 per block

  • in Emmy+ is 0.000183514; therefore #reorgs per month = 0.000183514 * 43200 = 7.92, as we can assume one block per minute, thus 43200 blocks per month;
  • in Emmy* is 1.0888e-08; therefore 1 reorg happens once every 1 / (1.0888e-08 * 2 * 60 * 24 * 356) years = 89.58 years, where we assume 2 blocks per minute.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.