"Change" Addresses?

[IveBeenBit]

Can someone explain to me what "change" is and what a "change address" is good for?

I do most of my transacting through the blockchain.info wallet, and it has an option to specify a "change address" among all my different bitcoin addresses, but it also has one that says to "return change to new address."

What difference does it make and how do I decide which option to choose?

Thanks.

[1715249586]

1715249586

[1715249586]

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[1715249586]

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[1715249586]

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[1715249586]

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[1715249586]

1715249586

[John (John K.)]

Can someone explain to me what "change" is and what a "change address" is good for?

I do most of my transacting through the blockchain.info wallet, and it has an option to specify a "change address" among all my different bitcoin addresses, but it also has one that says to "return change to new address."

What difference does it make and how do I decide which option to choose?

Thanks.

Change is just the spare bitcoins that is unspent during a transaction. Think of it like paying a $10 note for a $3 stuff, and getting the $7 returned.
Choose "return change to new address." if you'll like the change returned to a new address.

E.G:

You own an address , 1AXX with BTC10 inside.
You send BTC3 to 1BXX.
The BTC7 is sent to 1CXX, a new address in your wallet generated during this transaction if you chose "return change to new address."
The BTC7 is sent back to any change address you specify, if you chose the option to specify a "change address".

[DavinciJ15]

I have learned the hard way what "Change" is.  When I used the same wallet on many computers.    That is a big NO NO in the bitcoin world and I had thought someone had stolen my money when one day my wallet was empty.

You see when bitcoins are sent out the bitcoin program sends some coins back to you this is called "change".  Some times the bitcoin software will send all the coins out you have as one transaction to many people (you can pay more than one person in one transaction) and the "change" is the returning value minus what was sent to the individual you intend to send.  

So for example lets say I have 1 bitcoin and I send 0.05 bitcoins to you.  The bitcoin software could send all 1 bitcoins out in one transaction with two recipients one is you for 0.05 and the "change" of 0.95 goes back to me on another bitcoin "address".

When the software sends out the transaction it could use a new "change" address that my other bitcoin wallets do not have thus making look like my 0.95 was sent out along with the other 0.05 BTC.

This very thing happened to me and I freaked out.

A simple Rebuild got my bitcoins back.

So what you really want to know is what do you do with this "change" address option?  Well, lets say you wanted to keep all your coins at address 1DrucP7CraowYanGedAzdvWHsw33SrMbmD but use them from time to time.  The reason you may want to keep them at one address is to see how much you have at any block explorer site that allows you to look up balances on an address.  Thus you may want to specify that all "change" goes to 1DrucP7CraowYanGedAzdvWHsw33SrMbmD address.


Hope that helps

Davinci

[IveBeenBit]

Change is just the spare bitcoins that is unspent during a transaction. Think of it like paying a $10 note for a $3 stuff, and getting the $7 returned.
Choose "return change to new address." if you'll like the change returned to a new address.

E.G:

You own an address , 1AXX with BTC10 inside.
You send BTC3 to 1BXX.
The BTC7 is sent to 1CXX, a new address in your wallet generated during this transaction if you chose "return change to new address."
The BTC7 is sent back to any change address you specify, if you chose the option to specify a "change address".

I thought it was something like this. What is confusing me though is I have used the option to "return coins to new address" just to see what would happen. I've done this only a few times. So far, there are no addresses in my blockchain.info wallet that I did not specifically tell it to create - so, is it safe to say that for those few transactions, there was no "change" to return, and thus no wallet created?

[John (John K.)]

Change is just the spare bitcoins that is unspent during a transaction. Think of it like paying a $10 note for a $3 stuff, and getting the $7 returned.
Choose "return change to new address." if you'll like the change returned to a new address.

E.G:

You own an address , 1AXX with BTC10 inside.
You send BTC3 to 1BXX.
The BTC7 is sent to 1CXX, a new address in your wallet generated during this transaction if you chose "return change to new address."
The BTC7 is sent back to any change address you specify, if you chose the option to specify a "change address".

I thought it was something like this. What is confusing me though is I have used the option to "return coins to new address" just to see what would happen. I've done this only a few times. So far, there are no addresses in my blockchain.info wallet that I did not specifically tell it to create - so, is it safe to say that for those few transactions, there was no "change" to return, and thus no wallet created?

Most probably tha, yes. However, you could try and take a look by clicking the transaction itself. The output should consist of 2 addresses if there is change to be returned. The address with the other sum that you didn't send is the change address.

[Stephen Gornick]

So far, there are no addresses in my blockchain.info wallet that I did not specifically tell it to create - so, is it safe to say that for those few transactions, there was no "change" to return, and thus no wallet created?

Ya, I see the same thing (it doesn't generate a new address, but chooses an existing one -- just as if I has used the Any Address for change.)  

I've reported this on the Blockchain.info thread. 
 - http://bitcointalk.org/index.php?topic=40264.msg1019527#msg1019527