How Do You Choose The UXTO Order For A BTC Transaction?

UTXO selection for a BTC transaction is based on the following conditions:

  1. If any single UTXO matches the Target (spend value) exactly, it will be used.
  2. If the sum of all UTXOs smaller than the Target happens to match the Target exactly, they will be used. (This prevents bugs while sweeping a wallet.)

    However, condition 1 and 2 are less applicable when executing a transaction. In most cases, condition 3 type of the transaction is more commonly seen,
  3. If the sum of all UTXO smaller than the Target doesn’t exceed the target, the smallest UTXO that is larger than the Target will be used.