Updated: 23 October 2016
Coin control means to have granular control over the inputs and outputs of a transaction using the Graphical User Interface (GUI) of a bitcoin client. Not all bitcoin clients support coin control. Electrum is a client that has limited support for coin control.
Electrum allows you to select which addresses are used as inputs to a transaction. You can’t select where change goes, though.
Electrum coin control options are found on the addresses tab. By default this tab is not visible so make it appear by pressing ctrl+a or going to Wallet menu > Addresses. Right click on an address to see the coin control options:
The two options in the right click menu are:
- Freeze: Freezing an addresses means that Electrum will not spend coins sent there. When you freeze an address it’s colour changes to cyan :)A helpful shortcut to use with frozen addresses is the exclamation point (!). Enter that into the amount field on the send tab to have Electrum automatically fill the maximum amount.
- Send From: Select specific addresses and choose this option to use the bitcoins sent to those addresses as the only inputs to the transaction. You can select multiple addresses by holding down the ctrl key on your keyboard as you click on the address. This option will only appear if the addresses you have selected have a balance in them.
Electrum’s coin control implementation is limited but very easy to use. Control over change addresses would be nice but Electrum aims for an uncluttered GUI so it’s not likely that the developers will add this feature.