What is the lowest block time of any cryptocurrency? I don't mean the time of an individual block, but the target time per block.

What is the shortest reasonable block interval?

  • 2
    Lower block time is not a feature, it's an outright bug and security risk. There are very good reasons for the 10 minutes and any alt coin that tries to sell anything less as a feature is scamming people. Shorter blocktimes waste hashing power and favor centralization.
    – Jannes
    Feb 7, 2015 at 14:32
  • Unless centralization is what you want/need
    – MagikCow
    Feb 13, 2015 at 16:24
  • if that's their evil secret plan, then yes. Honest centralization can do away with the entire blockchain and be more efficient altogether.
    – Jannes
    Feb 13, 2015 at 17:51

2 Answers 2


There was a coin called Flashcoin that tried to do 6-second block times. I don't think that's being actively mined anymore as another Flashcoin appeared a year later (60-second block times).

Ethereum is planning a 12-second block time. Vitalik makes an argument for why that's probably the minimum for now here. Of course, ethereum hasn't been released yet, but Fastcoin with its 12-second block time is probably considered the lowest block generation time currently.


EOS has blocks that are published every ~500ms, so around two blocks per second. That's a contender for the top spot for sure

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