Coin Control

TL;DR:

Coin Control is an advanced feature that lets you manually choose which coins (UTXOs) to use when sending Bitcoin, instead of relying on automatic selection by your wallet

By manually selecting UTXOs, users gain more control over transaction fees, privacy, and how funds are spent.

Coin Control is available in wallets that offer advanced UTXO management, such as:

• Ledger: Using Coin Control in Ledger
• Trezor: Coin Control in Trezor Suite

Coin control is an advanced feature in many Bitcoin wallets that allows users to manually select which Unspent Transaction Outputs (UTXOs) are used when sending a transaction. This provides greater control over how your Bitcoin is spent (to reduce transaction fees) and can improve privacy.

Unspent Transaction Outputs (UTXOs): In Bitcoin, transactions are built using "Unspent Transaction Outputs" (UTXOs). Each UTXO represents a specific amount of Bitcoin that was previously sent to an address and is now available for spending.

Automatic Selection: Without coin control, a wallet typically selects UTXOs automatically, usually prioritizing older UTXOs to minimize transaction fees and potentially reduce the risk of spending coins associated with less secure addresses.

Manual Selection: Coin control lets you bypass this automatic selection and choose exactly which UTXOs you want to use for a transaction.

Using Coin Control offers several practical benefits:

• Saving on Fees:
• By selecting the right UTXOs, you can reduce the transaction size and therefore pay lower fees. This is especially useful during periods of high congestion on the Bitcoin network.
• Example: Choosing larger UTXOs instead of many small ones results in fewer inputs, making the transaction cheaper.
• Improving Privacy:
• You can avoid mixing funds from different sources, reducing the risk of linking transactions and tracking your financial activity.
• Example: Keeping funds from different sources in separate addresses to maintain privacy.
• Managing Change:
• You can decide which UTXO to use and where the change will go, preventing it from mixing with sensitive funds.
• Example: Sending change back to the same address to maintain traceability.

• When network fees are high, and you want to optimize your spending.
• If you want to keep funds from different sources separate for privacy reasons.
• To consolidate multiple small UTXOs into a larger one when fees are low, making future transactions cheaper.

Coin Control is available in wallets that offer advanced UTXO management, such as:

• Ledger: Using Coin Control in Ledger
• Trezor: Coin Control in Trezor Suite

1. Consolidate during low-fee periods:
• Take advantage of times when the Bitcoin network is less congested to combine small UTXOs into one larger output.
2. Check fees before sending:
• Use services like mempool.space to check the recommended fees before making large transactions.