Accessing the coin control panel
Once you have enabled Coin Control in the BitBoxApp settings, accessing its interface to manage your UTXOs is straightforward when you prepare to send Bitcoin:
- In the BitBoxApp, select the Bitcoin account you wish to send from.
- Navigate to the “Send” page. Enter the recipient's Bitcoin address and the amount you intend to send.
- On this sending screen, you will find a button labeled Toggle coin control. Click this button to open the Coin Control panel.
Interpreting the UTXO list: Addresses, amounts, and labels
The coin control panel shows a list of all Unspent Transaction Outputs (UTXOs) available in your selected account. Each UTXO entry typically includes:
- The Bitcoin address it's associated with.
- The amount of Bitcoin the UTXO holds.
- Any labels you have previously assigned to that address or transaction.
- UTXOs from change addresses are clearly marked as "change."
Labeling your transactions and addresses effectively makes identifying the right UTXOs much simpler and is highly recommended for a smoother experience.
Selecting specific UTXOs for sending
From the list in the coin control panel, simply click to select one or more UTXOs. These will be the inputs for your current transaction. The BitBoxApp uses the total value of your selected UTXOs to cover the sending amount and the necessary transaction fee.
How "send all" functions with coin control active
It's important to know how the "Send selected coins" function behaves when coin control is active. Normally, "Send selected coins" creates a transaction to spend your entire account balance.
However, if coin control is enabled and you've manually selected specific UTXOs:
- Clicking Send selected coins will only apply to the sum of those selected UTXOs (minus the transaction fee).
- It will not automatically include other unselected UTXOs in your account.
Keep this in mind to avoid mistakenly sending only a portion of your funds when you intend to send everything from the selected UTXOs.
Best practice: Labeling transactions for clarity
We highly recommend labeling your transactions and addresses, especially if you plan to use coin control regularly. Labels add essential context, transforming a list of complex alphanumeric addresses into a clear, manageable overview of your funds and their origins. This practice significantly reduces the risk of selecting incorrect UTXOs and makes your transaction history much easier to understand.
Key scenarios for using coin control
Here are some common situations where coin control can be particularly beneficial:
Scenario |
Benefit / Reason for using coin control |
Example |
Enhancing transaction privacy |
Break links between transactions by not merging UTXOs from different known sources. | Spending from a UTXO received from a KYC (Know Your Customer) source separately from one received via a private peer-to-peer transaction. |
Performing a satoshi test |
Prove ownership of a specific address to an exchange or broker by sending a tiny amount from its associated UTXO. | An exchange requires you to verify address bc1... by sending a small amount from that specific address. |
Consolidating small UTXOs ("dust") |
Combine many small UTXOs ('dust') into fewer, larger ones to potentially reduce future transaction fees and simplify wallet management. (This consolidation is a transaction itself). Learn more about UTXO consolidation. | Combining ten UTXOs of 0.00001 BTC each into one UTXO of 0.0001 BTC. |
Isolating funds for specific purposes |
Keep specific "coins" (UTXOs) separate for budgeting, tracking, or earmarking for particular uses. | Using a specific UTXO that was a gift to pay for a particular item, keeping it separate from your general spending funds. |
Tax planning and optimization |
Manage capital gains/losses by selecting UTXOs based on their acquisition date or cost basis, or preserve UTXOs that qualify for preferential tax treatment. | E.g., in Germany, Bitcoin held over a year can be tax-free. Use coin control to selectively spend younger UTXOs, preserving older tax-advantaged ones, or vice-versa for strategic tax outcomes. |
Potential fee optimization (Advanced) |
Influence transaction size (and thus network fees) by selecting specific UTXOs. | Choosing one older, larger UTXO might result in a slightly smaller transaction (in terms of data size and thus fee) than using many small UTXOs. |