After how many confirmations can I be sure that my transaction is not in a losing chain that ends up orphaned?

1 Answer 1


Leaving aside the fact that "sure" is a subjective concept...

The network uses 10 blocks and 60 blocks to unlock monero coming from a user transaction, and a coinbase transaction, respectively. These provide guidelines as to what the Cryptonote creators thought to be reasonably safe values.

You could also look at what number of confirmations exchanges require. Kraken uses 15 confirmations, for example (http://blog.kraken.com/post/155126375697/kraken-launches-monero-trading).

For clarity, there is no such thing as 100% sure. All you can do is estimate a probability and error bars.

  • Since Kraken requires 15 confirmations, does that mean there is a significant probability of a block getting orphaned after 10 confirmations or are the probabilities very low and kraken is being over zealous?
    – pl55
    Commented Jan 23, 2017 at 7:46
  • 2
    In this case, I believe they just set the number to match the time they use for Bitcoin (half an hour for both). As for the probability of a 10 block reorg, I can't give you an idea. It sounds pretty unlikely in the normal course of things, but if a deep pocket attacker (ie, Google, NSA, someone throwing lots of money at Amazon servers...) were to want to 51% the coin, it seems plausible in theory. I'd be interested to see an estimation of the probability myself :)
    – user36303
    Commented Jan 23, 2017 at 9:16

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