I'm using the blockchain API to make a "send to many transaction". In the recipients I only put other people addresses, but somehow the API sends the remainder of my balance back to me.

For example:


I had 0.01 btc in my wallet. I sent 0.0000543 BTC to two different recipients, but somehow my whole balance got spent and my 0.0097914 BTC got sent back to me. I didn't ask for this.

EDIT: It also happens on a singular transaction:


I've inspected the API calls and they are correct. My address is no where to be seen in it.

Why is this happening?

  • Thank you very much. Didn't knew it was called change and so google wasn't hepling.
    – joaoroque
    Dec 1, 2014 at 19:37

1 Answer 1


That's how Bitcoin works. Accounts don't really have balances, they have unspent outputs. You have to spend entire outputs, but you can return amounts to yourself to create a new "change" output that you can spend later.

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