I was wondering the other day how many unspent transaction outputs there are ?

If you just keep track of the unspent transaction outputs you could import private keys, know its balance and perform spends. How much data is this compared to the full blockchain ?

The biggest downside is that you would not have the full transaction list for a private key/address - just the transactions that you can use for future transaction inputs.


1 Answer 1


As of block 177778 (Apr 29, 2012 6:17:33 PM):

  • 2944702 transactions
  • 6904591 transaction outputs
  • 5376092 transaction inputs
  • 1528499 unredeemed outputs left
  • 642432 addresses with non-zero balance
  • Looking at the number of addresses with nonzero balance, an index versus 'list of blocks address has an unspent tx output in' I calculate would be less than 28 MB. It would then be quick to get the blocks from bitcoind and hence the key's transactions.
    – jim618
    Apr 29, 2012 at 18:43
  • 2
    Would a script that reports these numbers be available anywhere? Apr 29, 2012 at 20:59
  • I calculated it using a patch for bitcoind that scans the blockchain at startup, not very user-friendly :) Apr 30, 2012 at 0:53
  • 3
    A less time-specific answer to the question "How many unspent transaction outputs are there?" would be appreciated. Jun 14, 2013 at 22:01
  • @StevenRoose The number isn't fixed, so an answer would have to be "time-specific."
    – Geremia
    May 13, 2017 at 3:35

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