This article claims there are now 10,499,925 bitcoin (at the time of the reward drop from 50 to 25).

Weren't there supposed to be exactly 21,000,000 / 2 = 10,500,000 BTC mined at this point? What am I missing?

1 Answer 1


I suppose this is the culprit. If we add the duplicate 50BTC that is missing and the first reward from block 21,000,000, we would have 10,500,000BTC in total.

However, my calculations would be: 21000000 blocks (ranging from Genesis Block 0, to block 20,999,999) multiplied by 50 BTC, that would give us 10,500,000 With the duplicate transaction, that would be 10,499,950 BTC total.

  • 1
    IIRC there's another duplicate as well. If the OP's number is actually for block #210,000, this accounts for it.
    – theymos
    Commented Nov 30, 2012 at 13:21
  • 2
    What is a duplicate transaction? How does it make some bitcoins invalid? Is there a thread that discusses this?
    – ripper234
    Commented Nov 30, 2012 at 14:35
  • @ripper234 - This - bitcoin.stackexchange.com/questions/3030/…
    – ThePiachu
    Commented Nov 30, 2012 at 15:00
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    @PieterWuille Hmm, that's interesting. Any reason for that?
    – ThePiachu
    Commented Dec 1, 2012 at 9:18
  • 1
    Nobody knows, and there is no explicit comment about it in Satoshi's source code. However, no full node to date would allow him to spend it. Perhaps it was deliberate. Commented Dec 1, 2012 at 14:29

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