How balances are represented
Bitcoin does not store one balance at an address; it consumes unspent transaction outputs created by earlier transactions. Account-based chains commonly update an address balance and a nonce. The displayed wallet balance hides different underlying accounting models.
Selecting UTXOs and change
A Bitcoin wallet selects UTXOs as inputs and creates outputs for a payment and any change. Combining many small outputs can increase input count and transaction size, raising fees; the wallet may manage the change address internally.
A hypothetical wallet transaction
Suppose a hypothetical wallet has outputs of 0.4 BTC and 0.3 BTC and wants to send 0.5 BTC. It can use both inputs and create a recipient output plus change. The transaction may contain more data than spending one 0.8 BTC output. These figures explain structure, not current fees or a recommendation.
Why fees can differ
Bitcoin transaction fees depend on virtual size and the fee market, not simply the amount sent. More inputs or complex scripts can increase transaction size. Do not compare this directly with gas calculations on an account-based chain.
What to inspect in an explorer
An explorer can show transaction inputs, outputs, locking scripts, and fee rate. A displayed address balance can be the sum of many UTXOs, so an individual transaction's inputs and outputs do not alone establish the wallet's final balance.
Limits of each model
UTXO and account models make different trade-offs for security, privacy, and programmability. Neither model is automatically more anonymous or simpler; consider wallet implementation, address reuse, and each chain's state rules.