Is Possible Modified the change address?

[Sarah Azhari]

As I know, Electrum is HD (A hierarchical-deterministic) wallet, where the rest (out put) will be sent to the change address.

Like a day ago, I have 0.003 balance where 0.002 I sent to gambling site, and the rest+fee 0.001 (0.00997) automatic sent (HD) to 1st change address (yellow mark) on electrum. 



the question is,
is possible I modified change address?, example: I want to send 0.00997 to gxkum on 2nd address on pic automatically.

[nc50lc]

Yes, just pick your preferred change address and instead of inputting the "amount" in the designated text box,
use "pay-to-many", so 'pay to' should look like this (e.g.: when sending 0.01BTC):

Code:

payment_address,0.01
change_address,!

"!" indicates that the rest of your funds will be sent to that address.
You also have to use coin control if you have more than one coin (UTXO) available or "!" will consolidate all of your coins to your change address.

[hosseinimr93]

You also have to use coin control if you have more than one coin (UTXO) available or "!" will consolidate all of your coins to your change address.

Does  "!" always consolidate all the coins to the change address, if coin control isn't used?

Let's say I have two UTXOs.  UTXO_A is worth 0.04 BTC and UTXO_B is worth 0.06 BTC. I have received these two UTXOs in two different addresses.
Now, I want to send 0.05 BTC without using coin control feature. As far as I know, electrum would use the UTXO_B and wouldn't use UTXO_A at all. 0.05 BTC will be sent to the recipient and 0.01 BTC minus transaction fee will be sent to the address specified using "!". So, my coins won't be consolidated. Correct me if I am wrong, please.

[nc50lc]

-snip-

Does  "!" always consolidate all the coins to the change address, if coin control isn't used?

That's only the case in normal send, this method is using "pay to many" where there's a "!" amount among the outputs.
"!" is the same as clicking "Max" which will use all of the available balance.
Electrum will only select UTXO if there's no "!" amount; in which case, it will automatically select a change address.

The previous solution is more of a workaround since there's currently no option to manually set a change address.

[Sarah Azhari]

Yes, just pick your preferred change address and instead of inputting the "amount" in the designated text box,
use "pay-to-many", so 'pay to' should look like this (e.g.: when sending 0.01BTC):

Code:

payment_address,0.01
change_address,!

"!" indicates that the rest of your funds will be sent to that address.
You also have to use coin control if you have more than one coin (UTXO) available or "!" will consolidate all of your coins to your change address.

If i make example, like this?

You also have to use coin control if you have more than one coin (UTXO) available or "!" will consolidate all of your coins to your change address.

as I understand, if using coin control we can select change address into what we want. so as I can see in picture https://bitcoinelectrum.com/files/2021/02/paytomany.jpg , are the rest sent to 1 change address?

[hosseinimr93]

as I understand, if using coin control we can select change address into what we want.

With coin control, you don't specify the change address. Coin control allows you to select which UTXO(s) you want to be used.

Assume that you have three UTXOs and you want to make a transaction using a specific UTXO. You can go to coin control and select the desired UTXO.
Now, it's like that you only have that specific UTXO and the two other UTXOs won't be used for your transaction.

[nc50lc]

-snip-

If i make example, like this?
https://images2.imgbox.com/c9/1e/o7hOTLTN_o.png

Yes, the change will be sent to "bc1qh8...".

Additionally, while using that workaround, (like in the coin control tutorial) I'd recommend you to enable "Advanced transaction preview" so you can review your transaction before proceeding to send it.
That way, you'll see if the other output is going to the correct address with the correct amount, you can also close it if there's something wrong.
You can enable it in "Tools->Preferences->Transactions->Advanced preview" or clicking "Advanced" instead of "Send" when sending funds.
Take note that in the advanced preview, you'll have to click: 'Finalize', 'Sign' and 'Broadcast' to send a transaction.

-snip-

as I understand, if using coin control we can select change address into what we want. so as I can see in picture https://bitcoinelectrum.com/files/2021/02/paytomany.jpg , are the rest sent to 1 change address?

Coin control is only necessary if you have more than one UTXO in the "Coins" tab;
otherwise, you don't have to do it if there's only one UTXO or you want to consolidate your UTXOs.

It's the list in your Electrum's Coins tab ("View->Show" Coins to enable the tab), like this example screenshot from bitcoinelectrum.com:

[NotATether]

Yes, just pick your preferred change address and instead of inputting the "amount" in the designated text box,
use "pay-to-many", so 'pay to' should look like this (e.g.: when sending 0.01BTC):

Code:

payment_address,0.01
change_address,!

"!" indicates that the rest of your funds will be sent to that address.
You also have to use coin control if you have more than one coin (UTXO) available or "!" will consolidate all of your coins to your change address.

This should be documented somewhere on Electrum's website - or even better, as a tooltip in the "Pay" tab - if it's not already there.

Where did you find this information anyway? From the source code?

[nc50lc]

This should be documented somewhere on Electrum's website - or even better, as a tooltip in the "Pay" tab - if it's not already there.

The closest thing in the GUI is the "Send queue" invoice for max amount which has "max(!)" as the indicated amount.
But tooltip, I can't find any.

Where did you find this information anyway? From the source code?

I've been using that with "pay to many" for years and IIRC, there are older threads that mentioned the usage of "!" as amount (not in bitcoinelectrum)
In fact, I've suggested something similar before, like for example: https://bitcointalk.org/index.php?topic=5338398.msg57040834#msg57040834

[pooya87]

or even better, as a tooltip in the "Pay" tab - if it's not already there.

That's probably a bad idea considering the wide range of Electrum users. A newcomer may not know what that is and try something that could lead to some fund losses. Features like this are better left somewhat hidden and only for "advanced" users.